The rules for Dungeons & Dragons 5th Edition are quite clear (although often misinterpreted) about surprise attacks. Let’s restate them using other language:
At the beginning of combat, each combatant that is unaware of all opposing forces is SURPRISED.
Combat then starts as normal with initiative, and the normal initiative order.
However, any character that is SURPRISED has these restrictions:
- A SURPRISED character may not take reactions
- A SURPRISED character must skip their turn in the initiative order
- Once a SURPRISED character skips their turn, they no longer are SURPRISED and can take reactions and act normally.
Note that the requirement for surprise is for the individual to be unaware of EVERY opponent. If they can see one, they aren’t surprised.
In previous editions, surprise tended to be “everyone on a side is surprised, so they get a special surprise round”. This is no longer the case. Individuals on a side may not be surprised and can act while their companions catch up for what is going on. There’s no actual “surprise” round.
When a thief/assassin attacks, if the target was surprised but has already had (skipped!) their turn in the initiative order, then the special abilities against surprised targets no longer work. The thief/assassin needs to both surprise the target AND get better initiative than them.
What does unaware of all opposing forces mean?
Typically, it means that the opposing forces are hidden and unnoticed. For instance, every opponent made a Dexterity (Stealth) check that was higher than the target’s passive Perception score.
One exception is for combatants like Gargoyles which, in their stone form, can’t be identified as creatures. I normally rule that when gargoyles attack, they attack with surprise unless the characters were paying especial attention to them.
What happens when someone attacks during a negotiation, hoping to surprise the targets?
By the standard rules, everyone is aware of the attacker, so no-one is surprised, and initiative is rolled as normal.
However, you may find this unsatisfying. I’ve occasionally used this variant rule:
- The attacker makes a Charisma (Deception) check against every other combatant’s Passive Insight scores. (Yes, even their allies!) Those characters whose Passive Insights are less than the attacker’s roll begin the combat surprised!
That “Oh, I’m bored with this negotiation, let’s attack!” plays? Using this rule, they’ve got a chance to surprise their friends as well!
Can I ready an attack against opponents behind a closed door who are unaware of me?
No. You can’t ready an attack until initiative is rolled. However, it’s likely the opposition will be surprised at the start of combat. Roll Dexterity (Stealth) to determine which of your party are hidden when the door is opened. (This needs to happen otherwise the party will surprise the monsters FAR too often).
Can I ready an attack against opponents behind a closed door who are aware that I’m there?
No. You can’t ready an attack until initiative is rolled. When the door opens, roll for initiative normally and start combat!
Only comment I’d make is that I’m not sure I agree with your definition of surprise.
A quote from the book on surprise, “Any character or monster that doesn’t notice a threat is surprised at the start of the encounter.”
While the example in the book discusses hiding and stealth, the wording of the sentence that determines surprise says doesn’t noticed ‘a threat’. Not doesn’t notice a creature, enemy, player etc.
Therefor if they Ibelieved a person to be an ally right up until the moment initiative was called for (drawing a dagger behind their back etc) I think that in and of itself is justification to suppose your recommended insight check method via the rules as written.
I’m inclined to agree with Robert, but otherwise I must say I appreciate this article as I have just spent the past two days arguing surprise with a player.
It is poorly worded but in this case “a threat” is defined as a creature who wants to kill them. They do notice that a person has become a threat as soon as they take an action that would make them one. Since they are looking at them, they get a roll to determine who gets to go first. That’s the one of an initiative roll.