D&D 5E Action & Reaction

[SheckyS]

I'm a little confused about Reactions, and so I thought I ask for some opinions here.

My understanding is that on each round of combat, each characters gets to do each of the following:

Move (which may be broken up around the action)
Action
Bonus Action
Reaction

The most common Reaction is an Attack Of Opportunity (AOO), which is when an enemy in melee range moves out of range and you get a free attack against them.

My understanding is that AOO's do not need to be declared in advance, but that you can only perform one AOO per round (under normal circumstances). Also, it is my understanding that you can still perform an AOO eve if you have already used your Action for that round.

But reactions can also be used for other things, like waiting for something to happen. For example, let's say you are playing a rogue and you go first (or very early) in the initiative order. None of your allies are in melee range of an enemy, so you will not be able to get a sneak attack. So you decide to set up a reaction and say to the DM: "If any enemy comes into melee range, I will attack with my rapier."

So far, no problem. But now consider another case where you have already used your Action for the round and slew an enemy. Can you still prepare a reaction in case another enemy comes into range?


Are AOO's special in some way that they allow a reaction even when you have already performed an Action the same round?

Or are ALL reactions completely independent of Action?

Or do I have it wrong, and AOO's are only valid if you have not already performed an Action?

 

[BoldItalic]

I'm a little confused about Reactions, and so I thought I ask for some opinions here.

My understanding is that on each round of combat, each characters gets to do each of the following:

Move (which may be broken up around the action)
Action
Bonus Action
Reaction

Yes, but note that Action, Move and Bonus Action can only take place in your turn, whereas you can use your reaction during someone else's turn; and note that you don't necessarily get a bonus action, only if some special feature or circumstance grants you one

The most common Reaction is an Attack Of Opportunity (AOO), which is when an enemy in melee range moves out of range and you get a free attack against them.

My understanding is that AOO's do not need to be declared in advance, but that you can only perform one AOO per round (under normal circumstances). Also, it is my understanding that you can still perform an AOO eve if you have already used your Action for that round.

Correct. You can only make one Reaction per round and making an AoO uses it up.

But reactions can also be used for other things, like waiting for something to happen. For example, let's say you are playing a rogue and you go first (or very early) in the initiative order. None of your allies are in melee range of an enemy, so you will not be able to get a sneak attack. So you decide to set up a reaction and say to the DM: "If any enemy comes into melee range, I will attack with my rapier."

Yes, that's called "Readying an Action" and it uses up both your Action (preparing it) and your Reaction (doing it)

So far, no problem. But now consider another case where you have already used your Action for the round and slew an enemy. Can you still prepare a reaction in case another enemy comes into range?

Only if you have a feature that allows you to make two or more Actions on your turn; you need one to make the attack and another to Ready an Action. Normally, you couldn't do both.

Are AOO's special in some way that they allow a reaction even when you have already performed an Action the same round?

Or are ALL reactions completely independent of Action?

Or do I have it wrong, and AOO's are only valid if you have not already performed an Action?

You are allowed one Reaction per round, whether you have used your Action on your turn or not. (Indeed, you can use your Reaction before you even take your turn, then take your turn as normal.) So using your action to make an attack, for example, doesn't prevent you from using your Reaction later in the same turn to make an AoO. It does prevent you Readying an Action, though.

It's not that AoO's are special, it's that Readying is special. It might have been better if they had called it "Readying a Reaction" because that's essentially what it is.

Note, though, that even if you do use up your Action to prepare a "Ready", you are not committed to enacting it. You can use your Reaction for something else beforehand (for an AoO, for example) in which case the Ready is cancelled, or you can choose not to have it happen even if the trigger occurs, if you change your mind and want to save your Reaction for something else you think might happen.

 

[Hrothgar Rannúlfr]

Good questions.

I'm not an expert and am also interested in the answers.



Thanks!

 

[BoldItalic]

Good questions.

I'm not an expert and am also interested in the answers.

Thanks!

You're welcome

"Readying" takes a bit of getting used to, especially for people coming from earlier editions where there was no corresponding mechanic.

It's useful for circumstances that aren't already covered by particular rules. AoO's are spelt out in the rules, for example, and don't need to be Readied. Some spells (for example Shield) can be cast as reactions and don't need to be Readied. Some class features (for example the Rogue's Uncanny Dodge) allow you to use your reaction in special ways and they don't need to be Readied. It's only when you want to use your reaction in some ad hoc, creative way that isn't written into the rules that you need to Ready it, at the cost of foregoing your normal action to set it up as a special exception to the normal flow of events in the round.

 

[Mercule]

I think [MENTION=6777052]BoldItalic[/MENTION] covered it pretty well. I'll spin it a different way, in case that helps -- the answer is the same, though.

Combat is divided into rounds. Each round, every participant has a turn.

On your turn, you always get to do two things*: perform an Action and take a Move.

A Move is just that. There are different ways to move (crawl, fly, jump, walk), but they're all movement and use your Move "activity" (my term).

An Action is pretty much anything else you could do on your turn. There's a list in the PHB. You only get do perform one Action, though, full stop. For characters that get to attack twice, it's actually stated as "When you perform an Attack action, you may attack twice" or something very similar. You are not being granted an extra Action.

Some circumstances (equipment, class abilities, etc.) grant a Bonus Action. Examples are the Sorcerer's quickened spell or taking the Attack Action while wielding an weapon in your off-hand (TWF). No matter how many conditions you meet for getting a Bonus Action, you only get one. Also, you only get to do whatever the condition says you can during your Bonus Action. If you have nothing that gives you a Bonus Action, then you don't get one.

Worth noting is that you can mix and match your activities on your Turn. A 6th level TWF Fighter can step 5 feet, attack once with her main weapon, move another 10 feet, attack with her off hand, move another 10 feet and attack again with her primary weapon, and then move a final 5 feet.

A Reaction is an activity that you take during the round, but not on your turn. Like a Bonus Action, you need to somehow be granted a Reaction. Also like the Bonus Action, you only ever get one and you are restricted to doing exactly what it says. The opportunity attack is one, specific Reaction. It explicitly calls out (PHB p 195) that you make a single melee attack. Readying is another way to get a Reaction and it gives you a normal Action, but has its own restrictions (PHB p 193). Some spells (shield) grant Reactions, as well.

As another note, you only get one of each activity in a round. The only exception to this, to my knowledge, is the Fighter's Action Surge ability.

*Unless you're surprised, but let's handle one confusing topic at a time.

 

[psychophipps]

Also keep in mind that the term, "reaction" means that you almost always will use an action of this type during another character's turn. These actions are almost always a response to another character's action(s).

 

[Staffan]

On your own turn, you get to move, perform an action, and sometimes a bonus action (if you have something that lets you). You can also interact with an object.

In addition you get one reaction per round, defined as "start of your turn" to "start of your next turn". Reactions are taken in response to something else happening, usually on someone else's turn but sometimes on your own (e.g. you attack someone, they cast shield as a reaction, and you cast counterspell as a reaction).

The most common reaction is the opportunity attack - when a foe leaves your reach, you get to make an attack against them as a reaction. The second most common reaction is readying an action, which takes up both your action on your regular turn, and your reaction on someone else's turn. An example would be aiming at a doorway and shooting at the first thing that enters. There are also numerous class features and/or spells that are performed/cast as reactions: the rogue's Uncanny Dodge, the battlemaster fighter's Parry, or spells like feather fall or counterspell.

With the exception of readied actions, reactions don't affect actions taken on your regular turn.

So far, no problem. But now consider another case where you have already used your Action for the round and slew an enemy. Can you still prepare a reaction in case another enemy comes into range?

No, because you used your action to Attack, not to Ready.

Are AOO's special in some way that they allow a reaction even when you have already performed an Action the same round?

More the other way around: Ready is special in that it eats both your action and reaction. Note however that if you have readied an action, and you get another opportunity to take a reaction before the readied action triggers, you can still take that reaction but then you won't get the readied action (since you no longer have a reaction with which to do it).

For example, let's say a rogue is standing next to his barbarian buddy, and readies an action to attack the first foe that moves adjacent to them both (in order to get Sneak Attack damage). But then an enemy mage steps out of the shadows, and casts crown of madness on the barbarian, forcing him to attack the rogue - and the barbarian crits, dealing 40 damage or something ridiculous like that. The rogue then gets to say "Nope, I Uncanny Dodge that for half damage", using his reaction. Then one of the other foes moves up, giving the rogue a golden opportunity for a sneak attack... which they can't take, because they already used their reaction.

Or are ALL reactions completely independent of Action?

Most are.

Or do I have it wrong, and AOO's are only valid if you have not already performed an Action?

There's nothing preventing you from taking an opportunity attack even if you've already attacked earlier on your own turn.

 

[Hrothgar Rannúlfr]

So, you can ready an action, but you can't just choose to delay your action and then act later, right?

 

[pming]

Hiya!

There is no "delay" action in 5e...it's pretty much covered using the Ready action. If you are asking Does a character have to act on his Initiative number, or can he wait to use it later in the round?, the answer is... ask your DM. Most DM's wouldn't have any problem with that because, well, why would they? From a narrative (and common sense) side of things, there is nothing 'forcing' a character to attack a foe at some pre-defined time.

The key thing to remember when playing in (or DM'ing) 5e is that the DM is the rules, or at least ALL rules must first filter through him/her. Those rules are to be used to help run a fun and interesting game for all...the rules are not there to be slavishly followed without regard for their purpose (which is, basically, to help a bunch of folks sitting around a table play a make-believe imaginary game involving elves, knights, magic and dragons!). In other words...when a situation comes up, find a rule that facilitates that situation; or find the closest one and modify it. In the case of a "delay" type action, using Ready is probably the closest...so go with that and modify it on a case by case basis based around the current situation in-game.

Anyway, a player saying "I'll wait a bit and attack after the thief shoots his poisoned crossbow at this ogre, so I can attack the unhurt ogre if this one goes down"... is a perfectly reasonable choice. You don't need a specific rule to handle this, that's what DM's are for. IMHO, of course.

^_^

Paul L. Ming

 

[Greenstone.Walker]

So, you can ready an action, but you can't just choose to delay your action and then act later, right?

Correct.

Readying requires both a triggering condition and the chosen action.