Can a monk attack an enemy and then immediately hide?

Question

We have a monk in the party who believes that he can run up to an enemy, hit them in the back of the head, and then dive into the grass to hide until the next round.

His argument is that:

1. He is a wood elf so his Mask of the Wild allows him to hide in lightly obscured areas
2. Because he hit the target from behind and hid before they turned around they cannot "see" him

I feel that there should be a minimum distance that you must be away from a foe before you can attempt to hide in this kind of circumstance (I realize there are exceptions: complete darkness, invisibility, the creature cannot see, etc).

If i am not mistaken the sequence of actions performed were:

Step 1: Bonus Action: Step of the Wind to Dash behind the opponent; Step 2: Action: Attack Opponent; Step 3: Action: Hide.

So technically he attacked first , then hid in the long grass that was at his and his opponents feet. (just to clarify i believe the grass was just long grass ...not like they were fighting in a corn field or something clearly with cover)

Answer 1

Hiding takes an action

So, if the character is not able to attack solely using a bonus action or is allowed to hide as a bonus action he cannot hide after an attack.

Additionally in the PHB on p. 177 it says:

You can't hide from a creature that can see you clearly [...]

So you first have to get out of sight before taking the hide action.

For Wood Elves it is indeed possible when only "lightly obscured", but still he requires an action.

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Also, just to clarify how being hidden works:

Even if you might say, that the target did not turn around and couldn't see the Monk, he will not stay hidden! I do not know if your player meant it that way, but for clarification in the PHB on pp. 194f under "Unseen Attackers and Targets" it clearly says, that you give away your location when the attack hits or misses. And after you gave away your location you must hide again to benefit from "Unseen Attackers and Targets"! Even if you are under the effect of "Greater Invisibility".

Answer 2

The prequel to this answer is...

Where does the monk get a 2nd standard action from anyway? You only get one Standard action per round, unless you have something granting you additional actions.

Also you may only take a single Bonus Action per round, no matter how many options you have offering them...

But we'll ignore that, and assume he was Haste'd or something...

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If the monk is able to take each of those actions as described, then Yes, this course of action is possible.

The monk is capable of attempting to hide in the long grass.

Now it turns to the DM to decide how reasonable this measure of success is.

From Vision and Light, PHB p.183:

In a lightly obscured area, such as dim light, patchy fog, or moderate foliage, ...

So the DM must decide if the grass is long enough, and thickly grown enough to meet this definition of "lightly obscured".

Common sense should factor in here; 2-3 feet of even very thick grass would provide little cover against a medium-sized opponent, and none at all against a large opponent, but it would be like walking through a corn field to a small opponent.

Answer 3

You can't hit an opponent from behind in vanilla 5th edition. At least, not in a mechanical sense. There is no directional facing rule. PHB p.190: "In combat, characters and monsters are in constant motion." They are assumed to be able to turn and look about freely. This is reinforced by the inclusion of a variant rule for consideration of direction in the DMG on p.252.

I would rule against the player in this case, considering the tactic is intended to gain an arbitrary circumstantial edge based on a narrow interpretation of some rules, but not others.

Answer 4

In the action economy

Players get one each of the following on their turn:

• [Standard] Action
• Interact with object
• bonus action but only if one is triggered
• movement of base distance (half if sneaking).

To make a roll to hide...

He's moving, Hiding, and attacking all in one round.

The monk's bonus actions allowing an attack require the Standard Action to be an attack; in the case of the Ki driven one, it's not required to be a monk weapon, but for the free one from Level 1, it must be a monk weapon or unarmed.

The Monk's Step of the Wind only allows disengage or dodge.

So, while he might be "in the grass", he's not able to hide, and thus not eligible for any unseen attacker bonus.

A Rogue, however, can pull this off, as their Cunning Action allows hide as a bonus action. but note that I'd require the character to move AFTER hiding, at half speed, to be able to gain the advantage. And don't forget that grass tall enough and thick enough to provide adequate cover should also be difficult terrain.

A Fighter also might do it once per combat - thanks to their Action Surge.