[RPG] How much damage does the NPC assassin do in the first two rounds to a sleeping creature

assassindnd-5enpcpoison

A related concern in calculating the damage potential is does the poison stay on the short swords after the first round? I am trying to get a grip on how much damage does the NPC assassin does in the first two rounds to a creature who begins the encounter asleep. There are a couple of assassination attempts looming in our campaign that I need to get a better feel for. (This related question got me thinking).

Given

  1. NPC Assassin attacking first in a round (two shortswords, Multiattack)

  2. Target is sleeping (unaware of surroundings)

  3. A successful Dexterity (Stealth) check allows the Assassin to have surprise (but target wakes up if still alive once the attack happens).

  4. Assassin can expect additional opposition in Round 2, and needs to finish off the target to get out for a high percentage chance of mission success.

  5. Use average dice scores for ease of computation, since so many dice are being rolled

Find

a. The nova damage for the NPC Assassin in Round 1.
b. The damage in round 2

Relationships

Assassinate. During its first turn, the assassin has advantage on attack rolls against any creature that hasn’t taken a turn. Any hit the assassin scores against a surprised creature is a critical hit.

1 Sneak Attack (4d6), 2 hits with short sword, two saves versus poson.

Shortsword. Melee Weapon Attack: +6 to hit, reach 5 ft., one target.
Hit: 6 (1d6 + 3) piercing damage, and the target must make a DC 15 Constitution saving throw, taking 24 (7d6) poison damage on a failed save, or half as much damage on a successful one.

This is for me the tricky part. I don't think the poison gets doubled due to having a saving throw, similar to a giant scorpion's stinger. (Poison's a rider). It isn't clear to me that the poison stays on the shortswords once the first attacks/hits with the short swords are completed.

Key issues to resolve:

Is the poison still on the blades in round 2?
Is the target prone (attacked with advantage) on round 2? (For reasons to answer "no" to this, please explain)

What I arrived at:
Round 1 2x((2d6) + 3) + 2x(4d6) + 14d6 (Assumes neither DC 15 con save is made)
Round 2 (no crit assumed): 2x((1d6)+3) + 4d6 + 14d6. (Assumes neither DC 15 Con save is made)
That gets me to (26d6 + 6) + (20d6 + 6) = 46d6 + 12 = 173. (Each Con save versus poison reduces this by 12.25). Four saves drops it to 32d6 + 12 = 124.
The proposed target has 112 HP, which means the result is 'insta-kill' unless the die rolls are horrible on four attacks with advantage.

What I need from an answer

  1. Have I correctly calculated the damage done in two rounds if both attacks hit in each round?

  2. Is the target remaining prone for round two a poor, or a valid, assumption?

  3. Does the poison stay on the blades for the second round's attacks?
    If it does not, the numbers reduce significantly.

Best Answer

1. Damage depends on initiative.

Its important to remember that ALL the creatures roll initiative, even if they aren't aware of the dangerous situation, this sets them on when they can act once they are aware.

From PHB under Combat:

When combat starts, every participant makes a Dexterity check to determine their place in the initiative order.

Being a target makes you a participant, whether you want it or not. Furthermore, under conditions under unconscious:

  • An unconscious creature is incapacitated, can't move or speak, and is unaware of its surroundings.
  • The creature drops whatever it's holding and falls prone.
  • The creature automatically fails Strength and Dexterity saving throws.
  • Attack rolls against the creature have advantage.
  • Any attack that hits the creature is a critical hit if the attacker is within 5 feet of the creature.

As bad as being unconscious is, it does not remove you from initiative (or even give disadvantage)

Also important: From Sage Advice Compendium about being Surprised:

For triggering the rogue’s Assassinate ability, when does a creature stop being surprised?

After their turn in the round, or at the end of the round? A surprised creature stops being surprised at the end of its first turn in combat.

For further reading, there are other important questions regarding initiative and surprise:

surprise can act oddly if the target rolls high initiative.

See a related question about surprise here.

2. Depends on how initiative was rolled by both creatures.

If a creature is surprised, it is prevented from acting until the end of its first turn. When combat began, both characters rolled initiative. The sleeping character may have rolled higher than the assassin. However he didn't act as he was surprised (and asleep). However at the end of his turn, he can make reactions and he can take actions (on his next turn). Now the assassin still gets to attack, but the target isn't surprised. So when they take damage, they could technically even react to it, as the damage woke them up.

Second round, the target gets to go first, so he can stand up as normal.

3. Poison Stays.

For point 3. NPC abilities (while often named similarly to items and equipment) do whatever they say they do. Nothing more or less generally.

The assassin attack says:

Shortsword. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage, and the target must make a DC 15 Constitution saving throw, taking 24 (7d6) poison damage on a failed save, or half as much damage on a successful one.

Compare this to say a giant poisonous snake:

Bite. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 6 (1d4 + 4) piercing damage, and the target must make a DC 11 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much damage on a successful one.

What about the first one implies it would stop after an attack?