D&D 5E (2014) Hiding mid-battle; surprise or not surprise?

[insight994]

One of my players is an assassin rogue who likes to hide as a bonus action in mid-battle and comes back for a sneak attack. He says this gives him surprise, thus an auto-crit. I've let him get away with it so far, but it sounds very wrong to me.

So, hiding mid-battle; surprise or not surprise? That is the question.

 

[jaelis]

No surprise. The rules for surprise are clear it only happens at the start of a battle, and the rules for hiding are clear that the benefit you get is advantage on your attack.

If you want a way to think about or explain it: surprise happens when someone doesn't realize they are in fight. Even if they don't know about your assassin, they do know they are fighting and thus can't be surprised in that way.

 

[amarwain]

Let's look in "Combat step by step" (PHB:189):

1. Determine surprise
2. Establish positions
3. Roll initiative
4. Take turns
5. Begin the next round (repeat step 4 until the fighting stops)

So, your player is wrong.

 

[thethain]

Surprise is (almost) a condition which can only affect creatures at the first round of combat (or their first round entering an existing combat). It prevents them from taking any kind of action until the end of their first turn.

 

[Hriston]

Surprise is determined before combat when one or more of the participants are completely unaware of any threats at all on the other side. Anyone who is unaware of any such threats is surprised when combat starts (because s/he didn't know it was going to happen) and stays surprised until the end of his or her first turn. So no, surprise cannot be determined after combat starts.

 

[jaelis]

So no, surprise cannot be determined after combat starts.

I was trying to think of a case where you could impose surprise midcombat, and I think they do exist.

Easiest would be a situation where one character is for some reason unaware combat is going on. Like maybe they were sleeping soundly in a room and during the fight someone opens the door. Or they were petrified as an unaware statue and the effect is dispelled during the combat.

I feel like it would be reasonable to say those characters suffer surprise, even though it bends the RAW. At least, it seems like a legit grounds for a DM ruling.

 

[MiraMels]

I was trying to think of a case where you could impose surprise midcombat, and I think they do exist.

Easiest would be a situation where one character is for some reason unaware combat is going on. Like maybe they were sleeping soundly in a room and during the fight someone opens the door. Or they were petrified as an unaware statue and the effect is dispelled during the combat.

I feel like it would be reasonable to say those characters suffer surprise, even though it bends the RAW. At least, it seems like a legit grounds for a DM ruling.

Right, but surprise is still a condition that only happens (if it happens at all) as a creature enters combat, from their perspective.

 

[jgsugden]

Situations in which I'd allow surprise rounds 'during' a combat:

1.) A new combatant that is unaware of the combat enters the area of the combat (teleports in, moves into the area but could not hear/see the combat prior to arriving, etc...)
2.) A combatant let's their guard down entirely (the combatant believes all enemies are dead, the combatant believes all enemies are powerless to resist, etc...)

In both situations, the surprised being is effectively entering a new combat.

 

[jaelis]

Right, but surprise is still a condition that only happens (if it happens at all) as a creature enters combat, from their perspective.

Exactly, it's a question of the creature's perspective.

 

[MiraMels]

Exactly, it's a question of the creature's perspective.

Well, yes. But it still happens maximum once per creature per combat.

I took OP's question to mean, "can a player re-impose surprise on a creature after that creature has already entered the fray and is actively participating combat?", and my answer is "absolutely not, under no circumstances".