# What happens when allies occupy the same space?

According to "Moving Around Other Creatures" (PH p. 191 / SRD p. 92):

You can move through a nonhostile creature’s space. [...] another creature’s space is difficult terrain for you. Whether a creature is a friend or an enemy, you can’t willingly end your move in its space.

So it's possible for Alice to move into an ally's space, attack from there, then move out, the only penalty being that the ally's space counts as difficult terrain to enter.

If an enemy adjacent to the ally's space has readied a grapple against Alice and is successful, then Alice (unwillingly) ends her move in her ally's space.

Do allied characters in the same space suffer any negative effect?

Now the rest of Alice's allies do the same thing.

Is there a limit to the number of characters that can be stacked on a space?

What if Alice's ally was the one with the readied grapple?

Can you stack an ally on your space by readying a grapple to prevent them from leaving?

Unfortunately Mearls is not the proper authority on these matters...although he does try his best to help. Since he openly admitted he could not recall the rules on the matter and gave an educated guess...Crawford recalled them for him.

As per the intended RAW in PHB pg. 191:

"...you can’t willingly end your move in its space..."

Farther explained by Jeremy Crawford in the above:

"...you can't willingly end your move —any part of it— in another creature's space..."

So let's first clear up some confusion as to the phrasing of this rule.

• We know each creature get's a Turn (1 turn) in the initiative each Round; which starts being explained on PHB pg. 189.
• We know each creature may take 1 Action (Attack Action, Cast a Spell Action, Ready Action) and possibly 1 Bonus Action (there are several) during that Turn, with details also beginning on PHB pg. 189.
• We know from PHB pg. 190 that you may also move an equal distance up to your Speed score, and can use as much or as little of your speed as you wish as well as breaking that movement in between various forms of travel (walking, climbing, jumping, etc) and that there is no 'Move Action'.
• We know from the next section on PHB pg. 190 that you can break up your movement in between attacks and other actions.

With what we know from the above clearly written rules, it then becomes clear that when Crawford says you can NOT end ANY part of your move(as detailed above) in a creatures occupied space, he is referring to your Speed based Movement, and is NOT referring to ending your complete Turn, which can include any of the above listed. Your only choice is finishing your movement in an UNoccupied space near the creature in question, attack your target of choice, then move back through (if you have movement remaining) the occupied space making sure you (once again) do not end any part of your movement in that creature occupied space. Then you can end your turn. Keep in mind each time you move through the space it is difficult terrain and costs you extra movement unless you have the ability to ignore difficult terrain.

With this in mind... the only relevant question you have remaining perplexes me and I think there are only 2 outcomes.

1. If Alice tries to move through an ally using what we know from Jeremy but she is captured by a Ready Action Grapple from a hostile creature near the allys space.. the Ready Action you had in mind triggers (I am assuming?) the moment Alice is in range, interrupting her movement still in her allies space and effectively reducing her speed to 0 as per the Grappled condition.

Her movement has just been forcefully (unwillingly) stopped in another creatures space.

1. Alice tries to somehow move through a hostile creatures space but they Ready a Grapple Action. In this case the ready action grapple would trigger when she got within attack range, because a Grapple is always dependent on the Attack Action, which you must forgo in place of a grapple. An enemy could never Ready a Grapple to trigger when Alice steps into or on to thier space

• There are no rules that apply any penalty for this outcome.
• The space is difficult terrain anyway so the addition of Alice to the space changes nothing.
• We know a 5ft 'Space' is generally 5ft of 'effective creature threat' and not a humanoid/creature 5ft wide. So roughly 10 humanoids could stand grappled together in a 5ft space, which is 25 square ft.
• Stacking is another story entirely and then you are dealing with distance/height in Feet versus the creatures speed (which becomes 0 and so couldnt be tossed, thrown, or otherwise put on top of a grapple 'pile' higher than 1ft.).
• This is a good catch! Most of the issues raised still stand, though, since it's still possible for Alice to be interrupted and halted while moving through her ally's space. She just doesn't get to attack from there now. – Sebkha May 7 '16 at 4:26
• @Sebkha Yes I was just about to tackle that...since I noticed a valid question still stands! Though I am curious where it says a grappled creature is forced onto your occupied square? – Airatome May 7 '16 at 4:27
• "t is saying you can NOT end ANY part of your movement in an allies occupied space": no it doesn't, you are saying this. I personally think this is a very narrow interpretation; it talks about "your move" of which you only have one. – Dale M May 7 '16 at 8:00
• @DaleM As per Crawford: "...your move — any part of it - ..." . We know your movement can be broken down in to however many moves you want to make in between actions. So when Jeremy says ANY part of your move(ment) this is the ONLY thing he could be saying, otherwise the line makes no sense. No one has just one move, or 'your move' , but I have edited in a bit more elaboration in my answer which may help your thought process. – Airatome May 7 '16 at 16:58
• It's worth mentioning that when you are in the same space of another creature you suffer the squeezing effect so if you attack or do grapple context it could be at disadvantage. It would be interesting to debate whether occupying a square with an incapacitated ally/foe should still impose squeezing. – Ghilteras Jun 7 '17 at 7:39

Don't overthink this stuff, D&D 5 will tell you if there is anything special going on. Remember the 5-foot space is an abstract measure of the area a character controls, not that they physically occupy.

Do allied characters in the same space suffer any negative effect?

No.

Is there a limit to the number of characters that can be stacked on a space?

You mean apart from the physical one that a 5-foot space is 25 square feet or 125 cubic feet; this is a lot of human sized people - the current record for people in a telephone box is 14. A phone box is much smaller than a 5-foot space and if you are running combats with more than 14 people in them then they are going to take forever without trying to do stupid things like crowd everyone on one space.

Can you stack an ally on your space by readying a grapple to prevent them from leaving?

No, if you have readied a move to attack someone you are now hostile to them and they can't enter your space.

• Allied creatures in the same space suffer the squeezing effect (disadvantages on attack rolls and dex saving throws), so that bit is wrong. – Ghilteras Jun 7 '17 at 7:34
• @Ghilteras do you have a source for that? As per RAW, squeezing only occurs when a creature tries to move through a space that is too small for them size wise, not when they move through (or are forced to stop in) an occupied space. dale-m I'm not sure I buy your interpretation that readying a grapple against someone turns you hostile to them. Think of consensual grapples à la "I throw the dwarf" or simply a flying creature bringing along a flightless ally. – Entropy0 Feb 5 at 12:07