Combat rules you never knew

Part One

Part Two

Over the last three weeks, I have written a couple of posts examining some of the most easily overlooked rules of the Player’s Handbook. Today I am looking at Chapter 9: Combat. Spellcasting will need an article on its own.

Again, if I’ve made any howlers, let me know in the comments. And the usual disclaimer: this post is about rules as written (or, occasionally, rules as intended). Feel free to ignore them if it makes the game more fun!

Chapter 9: Combat

Three things need to happen before anyone takes their turn. (189)

‘Right, this negotiation is over. I want to throw a fireball!’

Hold on: combat doesn’t work like that. No one takes a turn until you have:

  1. Determined surprise;
  2. Established positions;
  3. Rolled initiative.

It is entirely possible that the other side is able to sense what’s coming and act before you do. That’s exactly why we roll initiative!

There’s no such thing as a surprise round. (189)

This is a vestige from previous editions. The first round of combat is the first round of combat. There’s no round zero.

You don’t roll Perception to see if you’re surprised by hidden enemies. (189)

You use the passive Perception score.

Surprised is not a condition. (189)

Being surprised means you can’t take actions, reactions, or move (and if you can’t take an action, you also can’t take a bonus action ­– see p 189). It has no effect on AC, saving throws, or anything else.

There are rolls for what happens when there’s a tie in the initiative order. (189)

Even very experienced players don’t seem to know this. Here’s the rule:

  • If there’s a tie between the player characters, the players decide between them who goes first.
  • If there’s a tie between DM-controlled characters, the DM decides who goes first.
  • If there’s a tie between player characters and DM-controlled characters, the DM deciders the order.

Lots of players think you should roll off or compare Dexterity scores. You can do. But it’s not rules as written.

There is no option to ‘delay’ in 5th edition. (189)

This was a deliberate design decision, explained in Sage Advice. Personally, I think it’s a good idea. If you’re not sure what to do, take the Dodge action. If you want to do something specific later in the turn, use the Ready action.

You can only take one action and one bonus action on your turn. (189)

Even if you have multiple bonus actions to choose from, you still only get to use one. You can also move, of course.

You can communicate ‘through brief utterances and gestures’ as you take your turn. (190)

A turn is only six seconds, after all. It is up to the DM whether you are able to speak during other creature’s turns.

Bonus actions and actions are not interchangeable.

This is clarified in Sage Advice.

When you use your reaction, you can’t take another until your next turn. (190)

This matters particularly for opportunity attacks and spells like shield or counterspell.

Switching weapons can consume your whole turn. (190)

A lot of groups handwave this, my own included, but, technically, it’s not that simple:

  • You can interact with one object for free as part of your movement or action. For example, you could draw or sheathe a sword.
  • Interacting with a second object requires you to use your action.

So, drawing a sword to attack a goblin ­– fine. Sheathing a sword and drawing a bow to attack a different goblin ­– not in one turn. The only way you can get round this is by dropping your weapon to the ground, which, according to Sage Advice, does not count as ‘interacting’ with an object.

Spellcasters with shields often end up breaking this rule. If you have a mace in one hand and a shield in the other, you cannot cast spells with somatic components without first stowing your weapon. There are 112 cleric spells in the Player’s Handbook: only 15 can be cast without somatic components. (One of them is healing word, you’ll be pleased to know.)

Donning (or doffing) a shield takes an action. (146)

Technically this is in Chapter 5, equipment, so I should have mentioned it in an earlier point, but it seems relevant to the point above.

You can move, attack, move in 5th edition. (190)

Yep! Much simpler than 3rd edition where you had to take a feat to do such things.

Moving through allies counts as difficult terrain. (190)

‘The space of another creature, whether hostile or not, also counts as difficult terrain.’  

You can’t stand up from prone if your speed is 0. (190)

Conquest paladins might be interested to know that you can combine this with your Aura of Conquest ability. A creature frightened in this manner has a speed of 0: if you knock them prone, they cannot stand up again. And there are surprisingly few creatures that can’t be knocked prone. Most of them are swarms, incorporeal, oozes, or capable of flight.

You can move through an enemy’s space – but only if it’s much bigger than you. (191)

A medium creature can move through the space of a huge or gargantuan creature, but it’s still difficult terrain, and you can’t willingly end your turn in its space.

This is the only way you can move through an opponent’s space short of becoming ethereal somehow. Tunnels can be deadly in 5th edition.

Even if a creature is prone, you still can’t move through its space.

This is clarified in Sage Advice. Again, the exception is creatures that are two size categories bigger than you.

If a flying creature is knocked prone, it takes falling damage. (191)

The exception is creatures that can hover or creatures that are flying due to magic (eg, the fly spell). That said, if a creature can hover, it is probably immune to being knocked prone anyway. There is only exception in the Monster Manual, and that’s the flying sword.

Xanathar’s Guide to Everything has rules for how quickly a creature falls. In essence, it’s 500 feet straight away and then 500 ft a turn. Of course, you only take damage when you hit the floor, so if you’re really high up, you might be able to save yourself in time.

Gargantuan creatures can be bigger than 20 ft by 20 ft. (191)

I wrote a whole post on this! Big creatures are BIG.

Squeezing gives you disadvantage on attack rolls and Dex saves. (192)

. . . and other creatures have advantage on attack rolls against you. Again: tunnels are deadly.

Playing on a grid is an optional rule. (192)

Yep! Theatre of the Mind is the default for 5th edition D&D – and I’m a big fan. Check out Sly Flourish’s guide to narrative combat if you’re worried about running a fight without a grid.

Moving diagonally is as easy as moving orthogonally. (192)

In older editions, a diagonal cost ‘1.5 squares.’ 5th edition simplifies this, but it’s a variant rule in the DMG (252) if you wish to make movement more realistic.

If you Disengage, your movement doesn’t provoke opportunity attacks for the rest of the turn. (192)

It’s not just the enemies you start out next to – you can move past a whole horde of goblins and provoke no opportunity attacks.

The Dodge action gives you advantage on Dexterity saves. (192)

It’s not just disadvantage on attacks against you. The Dodge action can be a wise action to take against enemies with area attacks (like dragons) or when you suspect there are traps nearby.

If you want to Help an ally with an attack, you must be within 5 feet of the creature targeted. (192)

You can’t do it range.

Helping only grants advantage on the first attack. (192)

Even if you miss, even if you have Extra Attack, it’s still only the first attack roll.

To Ready an action, the trigger must be perceivable. (193)

I would argue that ‘when the creature takes its turn’ is not a perceivable action.

You can Ready movement or an attack, but not both. (193)

‘When the ogre bursts through the door, I’m going to move forward and attack!’ Nope. You can move forward, or attack, but not both.

A readied action is technically a reaction. (193)

And remember, you only get one reaction per turn, so if you take an opportunity attack (a reaction) or cast shield or counterspell (both reactions), you lose your readied action.

Readying a spell requires concentration. (193)

I’m going to cover spells next week, but this is a specific point about the Ready action.

Readying a spell consumes a spell slot, whether it is triggered or not. (193)

For this reason, you might want to ready cantrips instead.

Searching is an action. (193)

If you want to look for something in combat, that’s an action. The DM will use passive Perception for general awareness.

Natural 20s automatically hit and natural 1s automatically miss – but only on attack rolls. (194)

It has no effect on other ability checks or saving throws. The only exception is death saves, where a natural 1 or a natural 20 has a particular effect.

You can target an invisible creature. (194)

An invisible creature isn’t necessarily ‘hidden’. You know their location. If you attack, you do so with disadvantage, but you don’t need to guess their location. To hide completely, an invisible creature still needs to take the Hide action, just like anyone else.

It is possible to deal 0 damage on an unarmed strike. (195)

‘On a hit, an unarmed strike deals bludgeoning damage equal to 1 + your Strength modifier.’ If your Strength modifier is negative, your unarmed strikes deal 0 damage.

Opportunity attacks occur before the opponent leaves your reach. (195)

This is not the case for all reactions – it’s a specific exception.

You can’t use Extra Attack on an opportunity attack. (195)

I pointed out this one in my first post. Extra Attack applies ‘when you take the Attack action on your turn’. An opportunity attack is on someone else’s turn, and is a reaction, not the Attack action.

Teleporting does not provoke an opportunity attack. (195)

Similarly, if someone or something moves you without using your movement, action, or reaction, that doesn’t provoke opportunity attacks.

Anyone can fight with two weapons – so long as you are wielding light melee weapons. (195)

It doesn’t require a feat or a class feature. However, both weapons must be light. You need the Dual Wielder feat to wield other weapons. (There seven melee weapons in the PH which are light: the club, the dagger, the handaxe, the light hammer, the scimitar, the shortsword, and the sickle.)

You cannot make an off-hand attack with an unarmed strike. (195)

Here’s a weird one: unarmed strikes count as melee weapon attacks but they are not melee weapons. You can only make an off-hand attack with a light weapon: an unarmed strike is not a light weapon.  

If your ability modifier is negative, it still applies to off-hand damage. (195)

You only ignore the ability modifier if it’s positive.

You cannot use a ranged weapon as part of two-weapon fighting. (195)

Again: light melee weapons only. Even Dual Wielder won’t help you here.

You can move a grappled creature with you, but your speed is halved. (195)

Presumably this applies equally to monsters with grapple attacks.

Allies can provide cover. (196)

Willingly or otherwise. If you are making a ranged attack and there is an ally between you and the target, the target likely benefits from half cover.

Hit points are not just physical damage. (196)

One of the reasons why D&D combat can feel unrealistic is that players (and DMs) tend to describe every hit like a grievous wound. ‘I stab him through the chest with my longsword, dealing . . . 3 damage.’

To quote the PH: ‘Hit points represent a combination of physical and mental durability, the will to live, and luck. Creatures with more hit points are more difficult to kill.’ Hit points are not wounds. In fact, the sidebar on p 197 states that when your current hit point total is half or more of your hit point maximum, you typically show no signs of injury. 

A tip: only describe these three wounds:

  • The wound that knocks an enemy to half hit points (you’ll need the DM to tell you this one);
  • The killing blow;
  • Critical hits.

Try it. Your combats will be faster and may even feel a little more realistic.

Critical hits don’t deal double damage. (196)

Critical hits have changed a bit between editions. In 5th edition, you roll all the damage dice twice, add them together, and then add any relevant modifiers as normal.

You can crit on a sneak attack, a divine smite, and even a spell attack. (196)

The spells don’t distinguish between ‘weapon attacks’ and ‘spell attacks’ here: so long as it’s an attack, you can get a crit.

Damage can kill you instantly. (197)

It’s there in the PH but only tends to come into play at low levels. Here’s the rule: ‘When damage reduces you to 0 hit points and there is damage remaining, you die if the remaining damage equals or exceeds your hit point maximum.’

It matters if you roll a 1 or a 20 on a death save. (197)

A 1 counts as two failures. If you roll a 20, you regain 1 hit point.

If you take damage at 0 hp, bad things happen. (197)

I’ll quote this verbatim:

If you take any damage while you have 0 hit points, you suffer a death saving throw failure. If the damage is from a critical hit, you suffer two failures instead. If the damage equals or exceeds your hit point maximum, you suffer instant death.

This is why the sanctuary spell exists – and why it’s a bonus action.

A stable creature must start making death saves again if it takes any damage. (197)

You’re not out of the woods yet.

Without natural healing, you regain 1 hit point after 1d4 hours. (197)

Curiously, though, there’s nothing in the rules to stop you from having a short rest while you’re on 0 hit points, so you might be better off spending hit dice.

By default, monsters die at 0 hp. (198)

The DM is free to rule otherwise, but most monsters don’t make death saves. For this reason, most monsters should run away when they’re losing a fight!

You can knock a creature unconscious if you ‘kill’ them in melee. (198)

5th edition doesn’t track ‘nonlethal damage’ like previous editions. In game terms, the decision to subdue an enemy only matters when they’re at 0 hp.

Temporary hit points do not stack. (198)

To quote the PH:

Healing can’t restore temporary hit points, and they can’t be added together. If you have temporary hit points and receive more of them, you decide whether to keep the ones you have or to gain the new ones.

You can’t mount anything. (198)

Hmm. ‘Phrasing.’ Maybe the PH puts it better:

A willing creature that is at least one size larger than you and that has an appropriate anatomy can serve as a mount

This is one of those situations where DM fiat comes into play. If a player wants to use something ridiculous as a mount, the DM is totally within their rights to say ‘no.’

You can land on your feet if your mount is knocked prone. (198)

It costs your reaction, though.

Not all mounts are controllable. (198)

The PH points out that ‘intelligent creatures’ act independently, and that you can only control a mount ‘if it has been trained to accept a rider.’ If it’s not domesticated, it rolls its own initiative, and your DM controls it, not you.

If your mount provokes an opportunity attack, the attacker can target you or the mount. (198)

Bye bye, horsey.

If you have a swimming speed, you can ignore the rules on underwater weapons. (198)

You have disadvantage on most melee attack rolls while underwater, unless you are wielding a specific weapon (eg, a dagger, a trident). However, if you have a swim speed – magical or otherwise – you can attack normally! 

Next week: spellcasting rules you never knew.

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