D&D 5e Rules – Flanking, Facing, and Fumbling!

And now some rules I DON’T use

Part of an ongoing (if occasional) series of 5e Rules notes.

One of D&D 5e’s strengths is trying to keep things simple. There’s a fair amount of complexity, but after 4e’s highly tactical structure, 5e leans on the KISS principle where it can.

That said, the DMG provides all sorts of optional rules that can add in a bit of crunchiness to things, or a bit of complexity (fun fact: Feats are optional rules.). Early on in my Princes of the Apocalypse campaign, I decided the following would not be part of my game, and I had no regrets.

Flanking

I gave some very serious thought to using the optional Flanking rules from the DMG (p. 251):

Flanking on Squares. When a creature and at least one of its allies are adjacent to an enemy and on opposite sides or corners of the enemy’s space, they flank that enemy, and each of them has advantage on melee attack rolls against that enemy.

When in doubt about whether two creatures flank an enemy on a grid, trace an imaginary line between the centers of the creatures’ spaces. If the line passes through opposite sides or corners of the enemy’s space, the enemy is flanked.

I’ve been playing D&D with miniatures my entire gaming career (hex and squares), so the whole “Theater of the Mind” that 5e tries to get back to after the uber-tactical 4e is, for me, just not something I can do. As such, Flanking (which was big in 3, 3.5, and 4) feels natural. “Get on either side of that dude; he can’t protect himself from all directions.”

The consensus (though not unanimous) conclusion of the Internet is that the 5e Flanking rule doesn’t work well:

Advantage is too big of an, um, advantage for this (“Advantage is an enormous benefit that lands 13 or higher 50% of the time, is almost twice as likely to crit, and has 1/20th times as likely to botch.”).
Maneuverability in combat is now easy enough (previous editions allowed Opportunity Attacks when walking around an opponent) that Flanking allows Advantage to come up too often, unbalancing everything (and deprecating a lot of other rules / Feats / actions that provide Advantage).

It’s been suggested that, as a house rule, rather than Advantage, a small uptick in the To Hit could be given (e.g., +1 or +2). This, though, flies in the face of 5e’s philosophy to avoid those endless kind of plusses/minuses that became overwhelming (it’s thought) in 4e and slowed everything down; that was the point of the Advantage/Disadvantage rules. (Roll20 makes it a little easier, but I understand their point.)

One suggestion I’ve also seen is that the Help move (PHB 192) takes the place of Flanking:

Alternatively, you can aid a friendly creature in attacking a creature within 5 feet of you. You feint, distract the target, or in some other way team up to make your ally’s attack more effective. If your ally attacks the target before your next turn, the first attack roll is made with advantage.

Help is way underutilized as a move; for player characters, there’s always a “But I want to be the one to hit him!” feeling. But the suggestion has been made that, esp. against a powerful opponent, this maneuver actually does more net good by helping a high-damage person hit more reliably, and its use doesn’t break anything.

So, for the time being, I don’t do the optional Flanking rules.

Facing

I am also don’t using the optional Facing rules (DMG 252), which are pretty crunchy and, honestly, are more of a PitA on a VTT because of the need to define facing of, and perform rotation on, the tokens. 5e has a sort of situational awareness vibe going on, and, as an Ease of Use rule, I’m fine with that.

Fumbling

This isn’t actually a 5e optional rule, but I grew up with Fumbling — having some sort of ill effect happen on a Nat 1, beyond just missing — being a Big Thing, and everyone sill always laughs about what happens when someone (preferably not them) rolls really poorly.

I eventually ran accross a ThinkDM article with the best reason for not having Fumbles (Nat 1 rolls) “do something bad,” especially in combat.

As characters advance, they get (in most classes) the ability to make multiple attacks each turn. This is particularly true with Fighters, who eventually can be making four attacks in a turn.But if you have a 5% (1/20) chance of fumbling in any given attack, the cumulative chances of fumbling in a round begin to climb …

Fumble chances with multiple attacks — Wait, what?

Missing is bad enough; a more disastrous effect becomes counterintuitive. Or, as the article notes, “A level 20 Fighter shouldn’t be dropping their weapon every 30 seconds.”

(A thought that comes to mind is having the “fumble” effect/table kick in only on the last attack of someone’s chain. So our intrepid fighter still only has a 5% chance in any given round, and if they want to play it uber-safe, they can sacrifice their last attack as they “take their time.” I’m not going to do that, but it would ameliorate a lot of the concern.)

Of course, a lot of that depends on the fumble table one uses. This was a table that described the “special effect” that came with a fumble — not just a miss, but a humiliating miss. This one, from the Arduin Grimoire, was all the rage back in my college days (though in those distant times it was rendered in cuneiform on clay tablets):

Arduin Grimoire Hargraves Fumble Table — Ouch

It was a simpler, more blood-thirsty time.

Still, at the level of abstraction 5e runs at, there’s really no good cause for this that can’t be covered by color text or, in case of a real run of bad luck, a symbolic penalty of some sort. That’s up to the GM to adjudicate.

Anyway, math.

ADDENDUM: Here’s an additional ThinkDM idea: a Fumble only occurs if you fumble all of your attacks on your turn. That means that higher-level folk are much, much less likely, though it can be, um, very unfortunate for that 1st level fighter. An even better alternative raised in the comments there would be to have a Crit or a Fumble provide Advantage/Disadvantage for the next roll for 1 turn. If I were going to adopt anything as a house rule (which I don’t think I am), it would probably be this last one.

D&D 5e Rules – Falling!

Into every game some character must fall.

Part of an ongoing (if occasional) series of 5e Rules notes.

Sooner or later, a question of falling comes up. Maybe it’s a pit trap, or a shove off a bridge, or an unsuccessful jump, or an expired flying spell, or …

It’s a good time to remember that the goal of 5e is not to recreate actual physics, but to provide easy, quick, workable verisimilitude, generally favoring the players. The falling rules are a good example of this.

The basics

The basic rule is simple:

At the end of a fall, a creature takes 1d6 bludgeoning damage for every 10 feet it fell, to a maximum of 20d6.

The creature lands Prone, unless it avoids taking damage from the fall.

It can’t be that simple, right?

Hans Gruber falling in Die Hard — Fun Fact: Alan Rickman was dropped before he was expecting it, leading to some great facial expressions as he fell.

Of course, that raises other questions, many of which are answered in optional DMG/XGE/TCE rules.

You will “instantly” fall up to 500 feet in the turn you begin falling. You then fall an additional 500 feet at the end of each succeeding turn.
- This mean no intervention by self or others during that first 500 feet if you don’t have a Reaction ability (such as Featherfall).
- But after that everyone, including yourself, may be able to do something.
- Note that though you fall 500 feet, you reach terminal velocity (so to speak) after only 200, given a max damage of 20d6.
- From a physics perspective, in five seconds you will fall 180m, or 590 feet, so this is actually pretty realistic, at least that first turn.
Flying creatures that need to actively move to fly will fall if they are (a) knocked prone, (b) have speed reduced to 0, or (c) lose the ability to move. If the creature is noted as being able to hover, or is being held aloft by some spell effect, this doesn’t apply.
- The first round they will fall 500 feet minus their current flying speed.
- In the case of the “prone” condition, they can on their next turn (if the ground doesn’t intervene) “get up” (using half their movement) to recover.
If you fall into water, make a Strength (Athletics) or Dexterity (Acrobatics) check; if you succeed, damage is reduced by half, per TCE.
If you fall onto another creature, per TCE, the target must succeed on a DC 15 Dexterity save to avoid being impacted by the falling creature:
- Any damage resulting from the fall is divided evenly.
- The impacted creature is knocked Prone, unless it is 2+ sizes larger than the falling creature.
- I’d rule that intentionally falling onto another creature probably takes an Dexterity (Acrobatics) check (perhaps against their AC?).
- This is different from creatures that attack by dropping onto their targets or leaping onto them from above. They will often have specific rules about damage they might take when doing so (e.g., the Piercer).

How do you avoid falling damage?

A number of ways.

The Featherfall spell is cheap and easy and is cast as a Reaction, reducing falling speed to 60 feet/round, and landing you gently on your feet. It can affect up to 5 targets within 60 feet, including yourself, and lasts for a minute.
The Monk ability Slow Fall is possibly a bit misnamed, but essentially you can use it as a Reaction to reduce falling damage by an amount of Monk Level x 5 hp.
- Earlier editions required something to slow you down (grabbing the wall, tree branches, etc.), but 5e does not; think of it as a three-point “hero landing.”

The Enhance Ability spell lets you pick “Cat’s Grace” as its DEX version. Among other things, it means the recipient “doesn’t take damage from Falling 20 feet or less if it isn’t Incapacitated.”
Using a Fly spell (etc.) will help, but only if it’s a fall of over 500 feet, otherwise you won’t have a chance to cast it before hitting the ground (unless you can cast it as a Reaction).
There are a variety of abilities that let you reduce damage to yourself or others that seem to apply here, e.g., Spirit Shield, Bastion of Law, Guardian Coil, Song of Defense.
Anything that gives you resistance/immunity to bludgeoning damage will likely help here, depending on how it operates.
Note that someone else using a Slow spell won’t help, as the falling creature‘s speed isn’t a factor in the damage or distance. (It doesn’t completely make sense, but them’s the rules).
Note that Athletics/Acrobatics do not, by RAW, do anything around reducing falling damage, though they have in previous editions. That’s all physics, baby.
- I would, though, support a house rule that a successful Dexterity (Acrobatics) roll vs. a DC equal to the damage you took might keep you from going Prone (stick the landing!).

D&D 5e Rules – Element vs Element!

When magic attacks “opposite” magic, things can get a little weird.

Part of an ongoing series of 5e Rules notes.

Okay, this is going to meander a bit.

Magical Water vs Magical Fire.

Can a magical water spell (or magical air/gust spell) drown (blow out) a magical fire spell?

The idea of this sort of encounter is natural, but the guidance from the rules is unclear.

Suggestion: Things can be countered unless it says they can’t be.

Take a Continual Flame spell:

The effect looks like a regular flame, but it creates no heat and doesn’t use oxygen. A continual flame can be covered or hidden but not smothered or quenched.

There is explicit text here saying that such flames cannot be smothered or quenched (largely because it seems that this is not a true flame, but an illusory flame light source). Fine. If something is written with such an immunity, they are immune. If not, they are as quenchable as normal flames.

Suggestion: Things are only countered if it says they are.

Rules As Written (RAW) philosophy is pretty literal. If a spell has an effect, the spell spells that out in its description. If it’s not mentioned, it’s not an actual effect.

So, for example, Thaumaturgy, Gust, Windwall, Create/Destroy Water, and Prestidigitation all explicitly state they can snuff flame. Tidal Wave, too. If a spell doesn’t mention that as an effect, it doesn’t happen.

(Note that Tidal Wave and others often specify “unprotected flames” — not drawing a distinction between a magical vs natural flame.)

Suggestion: Things can be countered if the counter-spell is a higher level than the original spell.

This is inspired by the Light/Dark setup. Darkness (2nd level) notes:

Nonmagical light can’t illuminate it. … If any of this spell’s area overlaps with an area of light created by a spell of 2nd level or lower, the spell that created the light is dispelled.

So there’s (in this case) some sort of “This quashing power is equal or greater to the power being quashed, so score” effect. This is a potential problem, though, because …

Curse you, Magic Items!

Magical items (or magical features of dungeon rooms) are often written without any indication of what spell effect they use, or what they are/aren’t immune to, or what level such a spell would be. Take the case of the magical burning spears wielded by Razorblasts in the Princes of the Apocalypse campaign. The Razorblasts can turn them on or off (though it isn’t indicated how), but there’s not even instruction on what would happen if a party member picked one up and wanted to use one. Some of the Earth Cult weaponry in that module is explicitly Earth Cult magic-specific, but that’s not the case with the fire effects noted. Are they flames an attribute of the Razorblasts, worship of Imyx, or the spears themselves? Only the DM know for sure (or guesses quickly).

There isn’t even a canonical weapon rule or example to draw from for something like those spears. The Flame Tongue weapons do more damage than the spears did. The Flame Blade 2nd level spell does as well (and is a weapon substitute, not enhancement).

Based on the above, the magical effect on the spears (which was +1d6 fire) is some sort of specialized elemental 1st level effect.

Okay, so it should be arguably easy to quench them, right?

But magic fire is not the same as physical fire. If you throw a bucket of water on a torch, the torch goes out, and trying to re-light it will be a pain because the fuel (the torch) is wet. But a blade that can have a magical fire turned on — well, the bucket of water will arguably quench it, but once the water is gone, it can be retriggered, unless the item’s rules have some weird “once a day” rule.

So what does this all mean?

It means doing some quick vamping as GM when someone creates one of these conflicts.

For example, you are in a room that has magical columns that, on a command word, begin to glow with a fiery heat, doing damage to anyone nearby. The amount of damage is spelled out. Nothing else is. (This, too, is from Princes of the Apocalypse). Jackie the Cleric casts a Big Wall of Water Spell (whatever) at the opponents in the in a room with magical columns.

It should have no direct effect on the magical columns, though, because those aren’t a flame source. Color text of special effects of steam and maybe therefore vision obscuring occurs. (Indeed, “I want to cover our withdrawal by shooting a big wall of water at the magma pillars” is a Rule-of-Cool clever idea that would probably net some Inspiration.)

It also knocks out the flames of the magical spears. But as of the opponents’ next turn start, they can reignite them because the water is not existing in perpetuity about their spearheads, and the momentary spell only overrides the permanent enchantment temporarily.

What, by the way, makes damage “magical”?

Slight digression, though it’s related to the topic. Let’s say William drops a Tidal Wave on people’s heads. Is that magical damage?

I mean, obviously, manifesting a huge block of water in the middle of a room is a magical effort (it’s a magical spell, in fact), but is the bludgeoning damage produced “magical”? Or is it effectively the same as produced by a mechanical trap that dumps a similar huge block of water over people?

5e goes with the following rubric to determine if something (including damage) is magical (via the Sage Advice Compendium):

Determining whether a game feature is magical is straightforward. Ask yourself these questions about the feature:

Is it a magic item?

Is it a spell? Or does it let you create the effects of a spell that’s mentioned in its description?

Is it a spell attack?

Is it fueled by the use of spell slots?

Does its description say it’s magical?

If your answer to any of those questions is yes, the feature is magical.

So is a Tidal Wave‘s attack is considered magical for purposes of “immune to bludgeoning damage not from a magical attack?” The answer is, it seems, “Yes,” because, for example, it is fueled by the use of spell slots. Even though, yes, there is no functional difference between it and a ceiling trap that drops a similar amount of water in a similar pattern.

What about the Infamous Tidal Wave vs Fire Elemental debate?

What happens if you cast a Tidal Wave at a Fire Elemental?

This is a debate only because

Tidal Wave has a calculable volume (but weird physics and dynamics to figure out impacts on surface areas, etc.) that mean you only take a fraction of that), and
Fire Elementals have a unique vulnerability / damage accrual measured by gallon and/or depth of water.

I have seen Reddit calculations from 6 hp damage to 25,000ish hp damage from such an attack, depending on the estimated surface area of a Fire Elemental and assertions as to how TW attacks work.

Rather than a bunch of crazy calculations (which are anathema to 5e), I as the DM would likely say, “It does its normal Bludgeoning damage (4d8), which the Fire Elemental Resists. However, it does double that amount (8d8) in Cold damage because the Fire Elemental is made of fire and is vulnerable to water. Also, the Fire Elemental doesn’t go Prone because they are immunite to that Condition.”

So probably no insta-kill for a 3rd level spell, sorry, but a butt-load of insta-damage, multiplied by every Fire Elemental in the area.

A OneD&D Note

This isn’t actually confirmed, but looking at the materials released so far regarding race-based magic, it looks like those rules may address some of the above, not just because it’s all kind of confusing, but because rather than arbitrary magical effects, documented magical spells are being used instead. That’s actually a good thing. Hopefully they will follow through with clearer answers and mechanics for all this.

D&D 5e Rules – Death (and Unconsciousness)!

Death comes for us all. But not necessarily this battle.

Part of an ongoing series of 5e Rules notes.

The point (very generally speaking) of D&D is to make the opponent worry about death. But it’s important for players to know about the rules, too, especially as they’ve changed since editions gone by.

Death (and Unconsciousness)

It’s important to understand a bit how down-and-out damage works in 5e. There’s no such thing as “going negative” here. When you are dropped to 0 (the bottom, you can’t go lower), you fall Unconscious (PHB 292): you’re Incapacitated, can’t move, can’t speak, are unaware, drop anything being carried, fail all Strength and Dexterity Saves … and Attacks against you have Advantage, and any hit is considered a Crit if attacked from 5 feet away.

But that’s the least worry you have. Because one of two things happen:

If the damage was so massive that the extra damage (theoretically beyond 0) equals or exceeds your HP maximum, you are dead, dead, dead.
Tick-tock …

If not, then you are “just” bleeding out, and need to start making Death Saves each turn (PHB 197). If you start a turn at 0 HP and are not yet stabilized, roll 1d20.
- On 10+, you succeed (a nat 20 counts as two successes); three total success, you become stable and will live.
- On 1-9, you fail (a nat 1 counts as two fails). Three total fails, you are dead, dead, dead.

If someone intervenes with a DC 10 Wisdom (Medicine) check, it will stabilize you, ending the Death Save checks.

Note that if someone inflicts further damage on you while unconscious, it counts as a Death Save failure; a crit (which is the auto-result of a hit from within 5′) counts as two fails. This also restarts the Death Save process. And if you take damage at 0 that is equal or greater than your normal number of HP, you die.

A stable creature stays at 0, Unconscious. It will heal 1 hp (and regain consciousness) in 1d4 hours (this does not count as a Short Rest). Healing spells are, of course, welcome to accelerate this process.

Note that this technically happens to the bad guys as well; the presumption, though, is hitting 0 kills a bad guy (they either fail their Death Saves, or you go around slitting throats after the battle). Best not to dwell on it. Powerful / significant enemies might get a Death Save process.

Taking Advantage on Death Saves

It seems clear that you can use Inspiration to gain Advantage on a Death Save (as it is, in fact, a saving throw, just not one associated with any Ability).

Indeed, as people can gift each other with their Inspiration, other folk could feed their Inspiration to a dying party member (“Don’t you die on me, man! Don’t you die on me!”)

As far as that goes, anything that helps on saving throws helps on a Death Save. So a Bless spell would work, too.

Knocking someone unconscious

Whether you want to avoid being a murder-hobo, or want to interrogate a prisoner who won’t surrender, you can intentionally knock someone out instead of death on opponents. (Vice-versa, too.)

You simply declare, on an attack that would have killed someone, that you are knocking them Unconscious (PHP 292) at the moment when the DM would say they’re dead. You don’t have to proclaim “subduing” damage in advance or anything; beating someone into unconsciousness is very much the same as beating them to death: it’s all in what you do after they fall down.

A foe rendered Unconscious this way is considered stable. They will wake up (healing 1 hp) in 1d4 hours. You can leave them behind, bind them and leave them behind, or change your mind and gack them. If you want to interrogate them, then you either need to wait, or use some healing magic on them.

Raising the Dead

There are a variety of spells that can bring back dead folk. There’s a good article here on it. In summary:

The Time Limit is how long after death the spell can be used. Note that Gentle Repose (Cleric or Paladin, 3rd lvl spell) can extend the time limit for a raise spell by 10 days if cast within the time limit for that raise spell.

1200px-Nuremberg_chronicles_-_Dance_of_Death_(CCLXIIIIv) — Dancing with Death

As implied under Spellcasting Services (PHB 159), these revivifying spells are not the sort of thing that you find being cranked out at your local temple, and even in a Big City they’re not a commodity service. Stolen souls, headless bodies, lack of bodies, death by fire, being turned undead, can all block some of these spells. Missing body parts can be an issue. Finding a 500gp diamond might not be easy, either. And many of these spells have consequences — limits on what they can restore (see article), being Necromantic in nature (ew), or the services that will be requested in return. (And clerical spells, esp. high level ones, have to be cast to a purpose sanctioned by the deity involved.)

Which isn’t to say it can’t happen, but don’t think of all this as the wild and wooly AD&D days when raising up dead PCs garnered as little consideration as murder-hoboing a complex (if wholly illogical) underground ecosystem.

D&D 5e Rules – Cover!

Hiding behind things is natural in combat. The rules are sometimes not so natural.

Part of an ongoing series of 5e Rules notes.

Like all things 5e, WotC set out to simplify the mechanics of how people were protected out on the battlefield by various objects.

5e set up basically four conditions:

no cover / uncovered (the default)
half cover
three-quarters cover
total cover.

The first and last usually get treated separately. It’s the partial covers in the middle that are of most interest here.

It’s difficult to talk about cover separated from a battle-map. Or, rather, if you are just running Theater of the Mind, cover is a matter of the GM asserting it (or agreeing to player assertions about it) by fiat. A lot of the below will depend on working on a square grid (extensible to a hex grid, if one likes; check out the DMG pages referenced below).

How about a drawing and a table?

Half and Three-Quarters Cover — Cover diagram from the DMG, p. 250 (Source)

The key here as to what cover a target has is counting the points on any one of their squares from any of the points in your square to see how many are blocked.

So here are the effects of cover on attacks, based on the rules here. This most often comes into play with Ranged attacks (including Spells), but

Points Blocked	Cover Type	AC and DEX Saves	Examples
1-2	*Half*	+2	Low wall, large furniture, narrow tree trunk, or a creature* (friend or enemy) directly in front of them
3-4	*Three-Quarter*	+5	Portcullis, arrow slit, thick tree trunk. Any of the target visible.

^{*A creature at least half as large as the target standing next to them. But … see my House Rules below.}

Points Blocked: As in the diagram above, on a grid, choose a (most favorable) corner of the attacker’s space. Trace a line from that corner to each of the corners of a square (any one) the target occupies. Based on how many of those points are blocked, you can determine the level of cover.

So if any of the points are blocked, there is at least Half Cover. But also note that, even if the all the corners are blocked (e.g., the target is behind an arrow slit), if you can see any of the target, it’s in Three-Quarter cover.

Total Cover: A target that cannot at all be seen / is completely concealed cannot be targeted by an attack or spell (though some spells can reach it in an Area of Effect — Fireballs, for example). Total Cover also starts to invoke rules for Hiding and the like.

Sizes of the characters involved can affect this (Small creatures behind larger creatures, etc.).

Multiple Covers provide the most difficult cover level. Arguably shooting an arrow past four people is more difficult than shooting an arrow past one person, but the KISS principle applies. As GM you can rule a cluster of Half Covers equal a Three-Quarters Cover, but the Rules As Written say that it’s still only Half Cover.

Combat and Cover at Corners

Consider the case in the picture — Fighter and Kenku squaring off (so to speak) at an architectural corner. Do the have cover from each other?

It might seem so, especially since the Move rules for grids indicate you can’t move through such a corner (PHB 192):

Corners. Diagonal movement can’t cross the corner of a wall, large tree, or other terrain feature that fills its space.

But for combat purposes, there’s no cover, because the kenku can take his top two corners (or the fighter his right two) and see (allowing for map/grid irregularities) along the wall all the other points of the opponent’s square.

It seems counter-intuitive, but there you are. Similar rulings can be made around doorways (the three squares on the other side of a 5-foot door have no cover from someone standing in the doorway on the other side, treating walls has having no thickness).

House Rule: Proximity to the Obstacle

Proximity to the Obstacle: Rules as Written say that obstacle are obstacles. My House Rule is a little more nuanced:

The attacker can ignore Half or Three-Quarter Cover if the attacker is closer to the obstacle than the target.

It’s all a matter of perspective. If an ally is right in front of me, I can weave around in my 5-foot square to get a clear shot; if they are right in front of the target, they provide much better cover for that target.

Take three examples that I will, for no particular reason, label as William (W) and Moony (M) dealing with a Goblin (G).

1) W---------->MG
2) WM---------->G
3) W-----M----->G

The normal use case is #1, where Moony is up there whomping on the Goblin, and William is behind, shooting a bow at the Goblin. That’s pretty clear; the Goblin gets Half Cover from Moony against William’s bow shot.

Consider case #2, where Moony was right in front of William. The penalty shouldn’t count here; it’s easy in a 5-foot space for William to shoot past Moony at the Goblin, adjust to shoot over Moony’s shoulder or to one side or the other. Assuming Moony isn’t doing jumping jacks in front of William, and is of a comparable size, that makes sense.

Use case #3 — where Moony is midway between William and the Rat is a bit more dodgy (so to speak). The angle to shoot around Moony is more difficult, though not as difficult as when Moony is right in front of the Rat.

So, what’s the ruling here? 5e would treat all three circumstances as providing cover, but I don’t like that. So I’ll borrow from the 3.5e rules:

Attacker can ignore the cover if he’s closer to the obstacle than his target.

At least as applies to Half and Three-Quarter Cover. In case #1, cover rules apply; in case #2, they do not; in case #3, William would need to take a step forward to fire and ignore the cover.

Some Other Notes

Note this is one of the few cases were 5e bakes in simple bonuses (vs using Advantage/Disadvantage). Assuming Advantage gives you about a +4 on a roll (it varies), that becomes too crude a measure for this.
There is a Variant Rule (DMG 272) about the chances of hitting the cover if you miss your target. KISS, man. Also, we’ll assume that people are being particularly careful not hit their allies.
Note that the Sharpshooter and Spell Sniper feats basically do away with Cover for their user. That’s pretty cool.

Update: OneD&D

In “Unearthed Arcana 2022 – Expert Classes,” the Hide action is allowed when behind Three-Quarters or Total Cover. The Sharpshooter and Spell Sniper feats ignore Half and Three-Quarters Cover, as in 5e.

D&D 5e Rules – Cone Attacks!

Cones are a D&D standard, but they don’t work well with battle maps.

Part of an ongoing series of 5e Rules notes.

This one is pretty straightforward, but also gets into complexities from how earlier versions of D&D have done it, and how some other systems do it, too.

Cones are not 90° angles

So that’s the main thing to remember. It was a mistake we made in our first game, and an easy one to because that’s how some other systems do it (like 3.5e and Pathfinder). But not 5e.

When playing on a battle map (if you are doing Theater of the Mind, then just do what the GM says), cones are defined as:

Coming from one of the corners of your square. (If you are running on a hex map, then cones are one of the few things that are easier that way, and please look it up yourself.) They don’t come from the middle of the square. They come from the corner. This is true for most spellcasting in 5e (DMG 251), and missile weapons, and line of sight — though the difference does not stand out in most cases.
The width of the cone equals the range from that corner. So the first five feet (square) the cone is one square wide. At two squares away, the cone is two squares wide. At three squares (the classic 15-foot cone), the cone is three squares wide. Etc.

Or, to quote rules:

Starting point, as the rules put it (DMG 251):

Choose an intersection of squares or hexes as the point of origin or an area of effect, then follow its rules as normal. If an area of effect is circular and covers at least half a square, it affects that square.

Width, as the rules put it (PHB 204):

A cone’s width at a given point along its length is equal to that point’s distance from the point of origin.

That comes out, I am told, as a 53° angled cone, not 90°.

Which all seems simple until you try to map it out on squares, because squares suck.

If you want to be really technical, you could use an actual cone template that is X feet wide when it is X feet out, and then pick squares that have a majority of their space included in the cone. But I find it easier to just say “Pick a single square, now pick two beyond that, now pick three along the same angle beyond that,” and let the player figure it out.

(I also have some square templates that can be dragged onto the VTT map which can sometimes help. But most cones are short enough that it’s not necessary.)

So, for example …

What does that look like, practically? Here is a simple drawing, which can be rotated in 90° increments:

So a straight cone on a square grid map. The question marks indicate a choice — pick one or the other to be in the cone (arguably, based on whichever corner you are casting from). As noted, at 5 feet the effect is 5 feet across. At 10 feet, the effect is 10 feet across (two squares). At 15 feet, the effect is 15 feet across.

Here’s another:

This one’s at an angle, and is serving double duty.

The red mage is doing a cone at an angle downward (remember this can be rotated in 90° increments, or rotated). At 5 feet, it’s 5 feet wide. At 10 feet it’s 10 feet. At 15 feet, it’s 15 feet wide.

(While cones emanate from a corner, they don’t necessarily target a corner.)

The yellow mage is shooting at a straight 45° angle down and right. This gets a bit more complex because of 5 foot increments and how you calculate diagonals on a square grid in D&D, but again, 1=1, 2=2,. 3=3

Player’s choice. As long as you are starting from a corner, following a line of some sort, and are X squares wide for an X square length of the spell cone, you’re golden.

If that’s still confusing … maybe go for non-cone spells. 🙂 (Though, to be honest, cubical spells have their own weirdities …)

D&D 5e Rules – Bounded Accuracy!

By keeping To Hit under control, 5e turns out very differently from earlier editions.

Part of an ongoing series of 5e Rules notes.

This is not a rule, actually, but a design philosophy that went into 5e, which gives it a very different flavor (and advancement path) than earlier versions. If you have no interest, you can skip it, though it does answer some questions about what sort of loot you’re likely to find in treasure hordes.

It boils down to a simple questions: Should Joe Shlub, the peasant, be able to hit Conan the Barbarian with his pocket knife?

rando vs. giant monster — Or, put a little differently …

Earlier versions would have basically said no:

Conan’s AC should be waaaaaay too high for Joe Shlub to ever hit.
So that’s what advanced most when you rose in levels and experience: your AC (by attribute and by powers, esp. magic armor), and your To Hit to counter it (again, through advancement and through +N Swords of Incredible To Hit).
So Conan has great TH numbers, but he needs them to wrassle with the fantastic AC numbers of the Ancient Red Dragons he’s being thrown against.

5th Edition answers the Joe Shlub question with a yes.

The goal is that everyone always has a chance to hit.
So we focus, in advancement and balance, on essentially the other side of the combat equation: damage and HP, the ability to deal it out and the ability to take it.
So Conan does tremendous damage when he lands a blow … but the dragon has triple-digits of HP.

In short, what most goes up in a 5e game over time is not TH and AC (though they do slowly increase), but Damage and Hit Points. As an example, by the end of the previous campaign we were playing (which brought us to the 19-20 range), we all had a buttload of HP, and the Rogue was doing like 7d6 Sneak Attack damage on top of his weapon. Accuracy and the difficulty of hitting something, instead, stayed within well-guided bounds … i.e., “Bounded Accuracy.”

Joe Shlub can hit Conan — but it’s only ever going to be a scratch. (A mob of Joe Shlubs doing a lot of scratches, aggregating damage output higher than Conan can individually, though … can be a threat.)

WotC has managed all this by putting some mathematical limits on things. Here are some articles that explain it well (the first gets into the not-difficult math, the second into the history):

The former in particular has the basic design table that drives everything, focused on difficulty to achieve something, and keeping strict caps on it.

DC or AC	Difficulty	To Break	Armor	To Hit
5	Very Easy	a glass bottle		an inanimate object
10	Easy	a wooden chair	No Armor	a badger
15	Medium	a simple door	Leather Armor*	a troll
20	Hard	a small chest	Plate Armor**	a dragon***
25	Very Hard	a treasure chest		a tarrasque
30	Nearly Impossible	a masonry wall(1 ft. thick)		a deity
with shield and +2 Dex modifier with shield **Adult Red Dragon is AC 19

This is also why Advantage / Disadvantage is so powerful. It not only simplifies the unruly flocks of plusses-and-minuses that 4e (and earlier) had, it gives a massive jump (roughly +4 in effect) to hit, but temporarily.

The bottom lines:

There is always a chance you can hit something (a nat 20, if nothing else). It can probably hit you back a whoooooole lot harder, but that’s not the point. As we’ve learned by doing, even a nassssty monster, surrounded by enemies, doesn’t have a long life expectancy (thus, even nassssty monsters are going to have minions to run interference). That’s because of the Action Economy.
Things that affect TH/Armor are going to be relatively rare and limited. Older systems handed out +3, +4, +5 weapons/armor like door prizes. In 5e, a +1 TH weapon is an expensive and relatively rare thing, available only in big cities. +2 is incredible, and unlikely to be found for sale anywhere. +3 is a thing of legends. You’re a lot more likely to find a sword that bursts into flames and does an extra 1d6 damage than a +1 sword.

This has been your Game Design lecture for today. We now return to your normal programming.

D&D 5e Rules – Bonus Actions!

A weird little mechanic that plays a huge role, once you figure out how they work

Part of an ongoing series of 5e Rules notes.

Bonus Actions are actually pretty easy, but they are not well explained in the 5e Players Handbook.

When can you use a Bonus Action?

On your turn, one of the things you may be able to do is a Bonus Action. The trick to understanding it is that you only get Bonus Actions that the rules specifically say you get. Certain rules give you a Bonus Action. You can only ever use one Bonus Action on your turn, and it can only be on your turn (you can’t use a Bonus Action in an Opportunity Attack, for example).

If you aren’t using or eligible by the rules for a Bonus Action, you don’t get one. There isn’t a “Bonus Action phase” in the turn or something. What you can do as a (single) Bonus Action has to come from a rule or ability applicable to your character.

Note that some spells have their casting time as one Bonus Action. These spells can only be used as a BA. Also, you cannot cast a Bonus Action spell if you have cast anything more than a Cantrip as your regular action.

Bonus Action Cry — Though that isn’t specified by the rules. (Source)

An Example

So, for example, my Rogue, Tener, started off with only one thing I could do as a Bonus Action (the one available to everyone): a second melee attack using Two-Weapon Fighting (PHB 195).

At second level Rogue, he got the class ability Cunning Action (PHB 96), which meant I could use my Bonus Action to Dash, Disengage, or Hide.

At third level Rogue, he got the Thief archetype ability of Fast Hands (PHB 97), which meant I could use my Bonus Action for Sleight-of-Hand, disarm a trap, unlock a lock, or Use an Object.

But I couldn’t use my Bonus Action to, say, Help, because that wasn’t a Bonus Action defined for my character. I could only do those specific actions defined for my Bonus Action in my rules.

Does everyone have Bonus Actions?

Some characters don’t have any Bonus Actions, at least at lower levels (except the option of Two-Weapon Fighting, if they choose it).

When can I take a Bonus Action?

One more thing about Bonus Actions: some have prerequisites and some have none. For example:

Cunning Action has no prerequisites. Whatever else I do on my turn, whenever I want in my turn, I can use the Bonus Action to, for example, Dash.
Two-Weapon Fighting says “When you take the Attack action and attack with a light melee weapon that you’re holding in one hand, you can use a bonus action to attack with a different light melee weapon that you’re holding in the other hand.” Therefore, you need to, in sequence:
(1) take an Attack action with one hand; then, later in your turn, you can
(2) use the Bonus Action to attack with the other hand.
You can do any other allowable things in between — chat with someone, Move, etc. But you can’t use the Bonus Action first in this case.
Monk’s Flurry of Blows speficies “Immediately after you take the Attack action on your turn …” In order to use the FoB Bonus Action, you have to
(1) take an Attack action, and then immediately (no Moving in-between)
(2) use the FoB Bonus Action.

In short, if there is a prerequisite, it must be fulfilled first. If the Bonus Action says “when you do X, you can do Y,” you can’t do Y, then X.

In summary …

The only time you get a Bonus Action is if you have a rule (usually from a class, race, or feat) that says you have a Bonus Action, and then it’s only good for what the rule says you can do with it. (And you can only do a single BA on your turn.)
Everyone has a Bonus Action for Two-Handed Fighting (allowing you to do the second attack as a Bonus Action). That’s pretty much it.
As a Rogue, your Cunning Action allows you to take a Bonus Action, but only to do a Dash, Disengage, or Hide. (This is a “restriction,” yes, but it’s actually granting you Bonus Actions that nobody else necessarily has. Similarly, if you take Thief, at 3rd level you can do a Sleight of Hand, disarm/unlock, or Use and Object as your Bonus Action on a turn.)

Can I take a Bonus Action to Help someone?

This came up early in my campaign. In short, unless you have a Bonus Action that specifically says you can Help on your BA, you can’t.

That said, “Help” (PHB 192) is a great Action for a character to take on their turn when they’re not sure what to do or if they don’t think their own attack on the BBEG will be effective, or if someone else will have a great attack.

For Rogues (again as it came up in my campaign) it doesn’t really come into play for allowing a Sneak Attack, though, because to Help for combat (giving Advantage) the Helper has to be adjacent to the target — which, if they are, means a Rogue can already Sneak Attack the target anyway (PHB 96) (though a Help would let you roll Advantage on the attack, which is not for nothing).

But, again, Help can’t be done in a Bonus Action unless someone has that specifically as something they can do as a BA.

D&D 5e Rules – Actions, Attacks, MultiAttack, Extra Attack, and Attacks of Opportunity!

There are some nuances in various attacks that aren’t immediately understandable in 5e

Part of an ongoing series of 5e Rules notes.

These notes came from early on in my 5e experience, since the delineations of what you could do in a given turn wasn’t immediately clear.

So, on your turn in a round of combat (which is basically when you need to be concerned about it), you can do the following, where/when your character is able to do so:

A Move (this can be broken into parts around your other activities).
An Action.
(If you have one) a Bonus Action.
A free interaction with the world around you.

Outside of your turn in the round, you may also take a Reaction.

Things you can do on your turn. (Source)

(See also my notes on the Action Economy about maximizing use of these elements.)

Actions

Actions include (PHB 192) Attack, Cast a Spell, Dash, Disengage, Dodge, Help, Hide, Ready, Search, Use an Object. Your class or a special feature may provide other Actions, and NPCs may have their own Action list as well.

It’s important to distinguish between an “attack” and the Attack Action.

An “attack” is when you roll a D20 (usually) to try to hit someone. Attacks may be made in the Attack Action, but they can occur at other times.
An Attack Action is one of your turn slots which may include one more more attacks in it.

Extra Attack vs. MultiAttack

“Extra Attack” is something Fighters (etc.) get as a class advantage at various times. It means that when you take the Attack Action, you can do multiple attacks (e.g., instead of a single longsword blow on the orc, you take two, or even three).

(This is different from doing a Two-Weapon Fighting (PHB 195) where the second attack is a Bonus Action).

“Multiattack” is something NPCs (and a few shapeshifting PCs) do — an animal’s claw-claw-bite, for example. It is its own Action, a Multiattack Action, not an Attack Action. Each of those attacks is usually also available separately, which is important with Opportunity Attacks.

Reactions, Opportunity Attacks, and Readying

Opportunity Attack (PHB 195) allows, as a Reaction (not during your turn, but during someone else’s), “one melee attack” when the target tries to step out of reach. Extra Attack doesn’t come into play (because it’s not giving you an Attack Action, just an attack): the Paladin doesn’t get to swing twice against a retreating foe, just once. Neither does Multiattack: when you move away from the giant bear, it can claw at you, but not claw-claw-bite.

Readying lets you take a specified Reaction (“if anyone steps in front of me, I will swing my sword at them”). . You can only Ready a single attack, not an Extra Attack or a Multiattack, because Reactions don’t take place on your turn. E.g., the Monk (PHB 79) notes that the Extra Attack is only on their turn. Ditto Fighter (PHB 72). Multiattacks are also intended only on the attacker’s turn.

(More on Readying an action here.)

Similarly, you can only use a Bonus Action on your turn (PHB 189). A two-weapon fighter can Ready an attack (or Opportunity Attack) with their rapier, but not their Bonus Action attack with a dagger.

D&D 5e Rules – Athletics and Acrobatics!

Two valuable skills that sometimes get confused.

Part of an ongoing series of 5e Rules notes.

Part of the confusion is … they are sometimes interchangeable, mechanically. But let’s first talk about the differences.

Strength (Athletics)

Succeeding in difficult situations while climbing, jumping, swimming, or other physical exertions. E.g.,

Climbing a cliff, or clinging to one while someone is trying to knock you off.
Jumping a long distance, or pulling a stunt mid-jump.
Struggling to swim or stay afloat in treacherous currents, or with something trying to interfere with you.
Forcing your way through something in your way.

Dexterity (Acrobatics)

Staying on your feet in a tricky situation. E.g.,

Running on a sheet of ice.
Balancing on a tightrope.
Staying upright on a rocking ship deck.
Performing acrobatic stunts (dives, rolls, somersaults, flips, tumbles)
Avoiding damage when falling. [Old school D&D, but not in 5e]

Using Athletics vs Acrobatics

In many way, you can narratively figure out which one makes sense, and different characters might use one or the other for the same action. Consider how Aragorn (an Athlete) would do something, vs. how Legolas (an Acrobat) would do it. A crowd of orcs to get past? Aragorn bulls his way through, while Legolas tumbles and leaps and dodges past, but the final effect is the same.

In a couple of cases in the rules there are explicit options as to which you can use.

Grappling: The Grappler rolls an Athletics check vs. the Grapplee rolling either with either Athletics (think “breaking free”) or Acrobatics (“slippling free”). If the Grapple succeeds, the Grapplee can repeat the contest as their action on their turn.

Shoving: Same as Grappling, only with a push-back or push-down as the result.

At the same time, the two skills are also quite different, something blurred by the Real Life fact that most Acrobats are also Athletes, and many Athletes have Acrobatic skills. People often think of Gymnastics as acrobatic (rolls and tumbles, and amazing acts on the balance beam). But those activities are also highly athletic. As has been commented, “Raw athleticism lets them climb things and jump through the air. It’s being acrobatic that allows them to do it gracefully or maintain their balance.” Or, as another person put it, “Athletics is when you’re going up, and Acrobatics is when you’re coming down.” The gymnast’s leap from the balance beam is clearly Strength (Athletics), but sticking the landing is Dexterity (Acrobatics).

Or if gymnastics isn’t your thing, consider a parkour routine; there are clearly both STR and DEX things going on there. (And CON, and INT, if not WIS, for that matter.)

To complicate things further, Abilities and Skills are not fixed in their combination. One can imagine a Strength (Acrobatics) roll being legitimately allowed, or a Dexterity (Athletics). Indeed, there is technically in 5e no such thing as a Skill check; everything is an Ability check, potentially modified by proficiency in a given Skill set.)

No huge conclusions here, just an observation about similarities and differences and what the fundamentals of two ambiguously-named skill sets are. Again, using the guidelines described above as guard rails, narratively figure out what it is that you’re doing. And, of course, note that both of these skills are good candidates for an occasional invocation of the “Rule of Cool.”

A House Rule

As noted above, in previous editions of D&D, Acrobatics could help save you from a fall by reducing its damage. That was explicitly left out of 5e, so I’m reluctant to re-insert it.

I would house-rule, though, that a successful Dexterity (Acrobatics) role might keep you from going prone after a fall, vs a DC equal to the damage you took (stick the landing!).

Bonus OneD&D Note:

According to the Character Generation playtest document, Grappling and Shoving are now part of the Unarmed Strike action — hit the target with an Unarmed Strike (D20 + STR mod + Proficiency) vs their AC.

If you were going for a Grapple, the target becomes Grappled, with a STR or DEX check each turn vs a DC of (8 + STR Mod + Proficiency) to break free.
If you were going for a Shove, you succeed.

This reduces the number of contests, but also reduces the use of Athletics and Acrobatics.

D&D 5e Rules – Advantage and Disadvantage!

Gone are the days of juggling a dozen plusses and minuses to a roll. And good riddance.

Part of an ongoing series of 5e Rules notes.

One of the 5e design mission statements was to Keep It Simple, Stupid. This KISS principle was a response to the ultra-crunchy tactical game which was 4e. I like miniatures and tactics, so I liked 4e, but it did, by focusing on numbers and formulae so much, drain a lot of color from the game. As I started up my 5e campaign, I constantly found myself running head-smack into things that 4e did that 5e did not, by design, and having to figure out why.

So what is it?

Rather than having players maneuver a blizzard of plusses and minutes on attacks, 5e tries to reduce it down to a simple set of questions for any Attack, Save, or Action Check roll:

Does the attacker (die roller) have, at the moment, an Advantage over the defender?
Does the attacker have, at the moment, an Disadvantage, compared to the defender?

Then:

If there’s no Advantage nor Disadvantage, it’s a Normal attack — roll 1d20.
If there is both Advantage and Disadvantage, it’s a Normal attack — roll 1d20.
If there is just Advantage — roll 2d20 and take the higher die roll.
If there is just Disadvantage — roll 2d20 and take the lower die roll.

Note that (KISS) these are not additive. There is no “Super-Advantage,” and no “Well, you have one Advantage and two Disadvantages, so that comes out to Disadvantage.” There is either just Advantage, or just Disadvantage; otherwise it’s a Normal 1d20 roll.

So what impact does this have?

There are some fancy graphs out there, but Advantage is roughly a +4 on a d20, statistically. Or, as put another way, “Advantage is an enormous benefit that lands 13 or higher 50% of the time, is almost twice as likely to crit, and has 1/20th times as likely to botch.” So 5e doesn’t hand out the status lightly.

Or, put in pictures (please feel free to ignore if math makes you twitchy):

Advantage and Disadvantage, plotted — What Advantage/Disadvantage does. (Source)

Having Advantage (blue) boosts your numbers up a lot, esp. in the middle range (trying to hit at least an 8-16); having Disadvantage (green) drags your numbers way down.

When do you have Advantage or Disadvantage?

There are a lot of conditions that create Advantage or Disadvantage (since there are very few conditions any more, except cover, that throw numbers, not Ad/Disad). A good survey can be found here:

A few common ones for combat:

Using the Dodge action during combat has any attack roll against you made at a disadvantage until the start of your next turn (if you can see the attacker). DEX saving throws while Dodging are made with advantage. (Note to GMs: bad guys should Dodge a lot more than they do.)
Using the Help action during combat can give an ally advantage in one of their own ability checks before the start of your next turn (see “working together”). Alternatively, it can provide advantage on the first of an ally’s attack rolls against a monster.
Attacking an enemy while hidden (if they don’t detect you approaching) or otherwise unseen grants you advantage on attack rolls. Conversely, attacking an enemy you can’t see has you making the roll with disadvantage.
Ranged attacks whose target is within a weapon’s long range (but not within normal range) have a disadvantage on the attack roll.
Ranged attacks (including rolled spell attacks) in close combat (within 5 feet of a hostile creature who can see you and isn’t incapacitated) have a disadvantage on the attack roll. (Spells that require a Saving Throw don’t have this problem because they have no attack roll.)
Attacks made while prone are at a disadvantage. Attacks at 5′ made on someone who is prone are at an advantage, but attacks beyond that are at a disadvantage.
You can spend a your point of Inspiration to make an attack, save, or action check at advantage.

Advantage also shows up as a balancer. Kobolds, for example, have a Mob Tactics ability; if a kobold is next to an ally in combat, they each get Advantage on their attack roll. Thugs and Wolves have analogous abilities. That makes them more of a threat than you might think.

How do I roll Ad/Disad?

Normal physical tabletop, just roll two D20s and pick the higher (or lower) one as need be.

The Roll20 VTT standard 5e character sheet provides multiple ways to roll advantage, set through the Settings (gear icon) on the sheet toggle (CORE|BIO|SPELL|gear):

Advantage Toggle — You’ll see a ADVANTAGE | NORMAL | DISADVANTAGE toggle at the top of the character sheet which you can adjust for each roll. [This is what I do, because I like to be sure I have all my settings right and am not throwing more dice than needed.]
Advantage Query — For each Attack/Save/Action Check roll, you’ll get as pop up window asking if you have Advantage or Disadvantage. [I find this annoying, myself.]
Always Roll Advantage — This will roll 2d20 on everything, then you can apply the roll (higher number for Advantage, lower number for Disadvantage, left-hand number for Normal). [This is a very common way people do this, and for the DM the monsters are all done this way.]
Never Throw Advantage — Always just roll 1d20; if you need to roll a second die, do it again.

D&D 5e Rules – Action Economy!

It’s a bit Inside Baseball, but understanding it can be the difference between PC Life or Death

Part of an ongoing series of 5e Rules notes.

So this is less rule than game design philosophy. It feels a little Inside Baseball, but understanding it is fundamental to understanding a lot of the reasoning behind the rules in 5e, and in why the game behaves the way it does.

What is the “Action Economy”?

In short, action economy means what a character (or NPC or creature) can do each turn. How many attacks can they make? How many abilities can they use? How many spells can they cast? A lot of the rules I’ve researched in here orbit around that concept of action economy.

Essentially,

the larger your action economy ⇒
the more things you can do in a turn ⇒
the more powerful you are

And that’s true for individuals, as well as for groups.

A big part of character advances are adding more attacks, more Bonus Action options, etc. Similarly, more powerful monsters have more attacks and actions in a turn (including legendary and lair powers).
All things being equal, the side that has the greater numbers of combatants has an advantage in combat, because their action economy, the opportunities they have for success in combat, is greater.
Bounded Accuracy , as one person put it, “makes everybody dangerous no matter how weak but does so at the cost of making everyone vulnerable no matter how strong.” Which means, by implication, over time a bunch of weak (but dangerous) characters can overwhelm a strong (but vulnerable) one.
PCs often have advantage in combat because encounters often have more PCs vs fewer (but individually more powerful) enemies. Sure, that monster can do three physical attacks, or maybe a big spell effect. But PCs much more often get more Attacks, Spells, Bonus Action abilities, etc., than enemies, individually or (and this is important) in aggregate. They often also get specialized Reactions others than Opportunity Attack. This only starts to partially equalize when you get up to epic creatures that have legendary and lair actions, but even there, numbers tell.
Everything you can do is part of your action economy: Actions, Bonus Actions, Reactions, and Moves. The more you can set yourself up (tactically, in a battle, or strategically, in your character design) to do something effective with all of those options in a turn, the more effective (and deadly) your character will be.

5e Player Action Economy — All the things you can do as a player. Source

In short, the action economy is your range of actions in a round (see above), and by extension, maximizing your effectiveness by using as much of that economy as possible.

How do GMs cope?

GMs bitch a lot about this: the boss fight that’s got the arch-critter-demon you’ve had the players trembling about for months … ending with the boss going down in two rounds as the 15 attacks the party can generate per turn (action economy!) overwhelms the 4-5 the boss can.

What (just to offer notes) do GMs/module writers do in the face of this?

They add Minions! They’re not just color text — they help balance the “overwhelming numbers vs very powerful foe” equation by mitigating the former so that the latter can get some licks in.
As mentioned, epic-level legendary creatures — dragons, liches, beholders, etc. — can get legendary and/or lair powers, which basically add to their action economy (and hurt like the dickens). GMs often add these non-canonically to other bosses, too.
Do other things to add to a boss’s action economy. One suggestion that seems to have legs is making bosses, in short, multiple creatures (with different capabilities and HP pools and initiatives) presenting as a single creature.
Split the Party. If the party can’t bring all of its power to bear — because it’s split up (by its own choosing or through an external force), or maybe because the attack vectors are limited (a narrow hallway, perhaps), it’s action economy is restrained.

The converse to all of these can be used (usually by the GM) to weaken a boss that seems too big to tackle.

Some good articles to check out:

GM counter-tactics (as, ahem, thought experiments):

D&D 5e Rules – Overview and Table of Contents

I’m trying to make use of stuff I’ve researched and written up for my players to help the community at large.

I’ve been DMing D&D going back to the AD&D v1 era, and recently wrapped a 2½ year 5e campaign. One of the things I ended up doing for that was writing a lot of “rules summaries” explaining or exploring (or in some cases “house ruling“) on concepts or specifics that need a bit more explanation than what shows up in all those expensive D&D books.

We were using Roll20, so I’d been keeping those rules summaries in the Campaign Forum there for my players, but I think I’m going to start posting copies of them here on my blog, as a longer-term (and more searchable) resource.

A few caveats:

I tend to try to go with Rules As Written (RAW) when given a choice. When I need something more clear than that, I lean heavily on the RPG Stackexchange, because those folk are rules lawyers in a very reasonable fashion.
That said, this is still just me saying things, though I try to document what I say. If you, or your DM, think differently on any of this, that’s up to you and your table.
There are cases where I go with house rules that I think make things easier, more sensible, more fun — without, I hope, gutting major gaming subsystems.
This is all going to be focused on D&D 5e — and with One D&D (or whatever it turns out being called) ramping up, all or most of this may be obsoleted (claims of backwards-compatibility notwithstanding). Caveat lector.

House Rules!

… to be continued …