A System to Simplify Large Combats: Attacking as a Unit

[Damon_Tor]

Mostly this is because the necromancer is making things difficult to manage, but it could be applied to any situation where a horde of identical creatures attack something:


Attacking as a Unit
When five or more identical creatures attack a single target, they do so as a UNIT, making a single attack and damage roll.

1. The controller of the creatures (usually the DM) declares which units are attacking and what the target is.
2. He makes an attack roll for those creatures as a unit. Of one of the creatures in a unit has advantage or disadvantage, they all do. The result of the attack roll compared to the target's AC decides what percentage of the attacking creatures hit the target, rounded down. If the result of the attack roll is exactly equal to the target AC, half the attackers hit. Every point above or below the target AC adds 5% to the number of attackers that hit, so if the result is AC+10 or more, all the attackers hit. If the result is AC-10 or less, none of them do. A natural 20 on the dice results in a critical hit as normal, but it's not an automatic hit for all creatures: you must still determine what percentile of attacking creatures hits, and only creatures that hit double the amount of damage dice rolled.
3. He makes a damage roll and multiplies the result by the number of creatures that hit.

So for example, if a Unit of 12 tribal warriors makes a two-handed spear attack (+3 to hit, 1d8+1 damage) against an ogre (AC 11) they've surrounded, they roll twice, because they have advantage from their pack tactics ability and the best dice of the two they roll reads 12. 12+3 is 15, and beats the Ogre's AC by 4, which means 8 of them (70% of 12, rounded down) of them hit. They roll damage and get a 7. Multiplied by 8, the unit deals 56 damage to the ogre this turn.

Note: the attack modifiers and damage of the creatures must be identical. If six of the creatures are using different weapons, they cannot attack as a part of the unit, though they could attack as a unit of their own. Similarly, if any number of creatures have a +2 bonus to attack rolls from a magical effect, they cannot attack as a part of a unit that does not have that buff.

Does anyone forsee any obvious problems with this system? Do you think it would actually reduce the management of the creatures, or just create new problems?

[Kane0]

I like it. It feels like a nice compromise between having all the extras and streamlining play.

[Trask]

I agree, good rule. Calcing up percentages would be a little annoying to me as a DM, but the alternative is even more annoying.

[McSkrag]

As a DM it seems fair and balanced and I would use it.

This is an edge case, but I think you might need to account for very large numbers of enemies.

For example, if you have 100 dracoliches all attacking a smarmy goodie-goodie paladin, I think they should attack in groups of 10-20 to help ensure the attacks and damage average out. You wouldn't want all 100 to roll a 1 and then the paladin is just sitting there laughing in their skeletal faces.

I'll put it into practice and see how it goes.

[Kane0]

Presumably they wouldn't all be able to, due to reach and movement.

[UrielAwakened]

This is basically what Dungeon World does, except they add a flat bonus for each creature above the first that attacks at once.

It works.

[Lunali]

The DMG already has rules for handling mob attacks, though it really cuts down on the randomness.

Essentially, you take the number the enemy will need to roll to hit the target. That number determines how many attackers are needed to score a hit, you then divide the number of attackers by the number needed to get a hit and you get the number of attackers that hit per round. Those that hit hit with all of their attacks, but don't crit on any.

For example, if you need to roll a 15-16 to hit the target, you need 4 attackers to score a hit. Divide the number of attackers by 4 to find out the number that hit.

[Kane0]

The DMG already has rules for handling mob attacks, though it really cuts down on the randomness.

Essentially, you take the number the enemy will need to roll to hit the target. That number determines how many attackers are needed to score a hit, you then divide the number of attackers by the number needed to get a hit and you get the number of attackers that hit per round. Those that hit hit with all of their attacks, but don't crit on any.

For example, if you need to roll a 15-16 to hit the target, you need 4 attackers to score a hit. Divide the number of attackers by 4 to find out the number that hit.

So all math and no rolling?

[Damon_Tor]

The DMG already has rules for handling mob attacks, though it really cuts down on the randomness.

Essentially, you take the number the enemy will need to roll to hit the target. That number determines how many attackers are needed to score a hit, you then divide the number of attackers by the number needed to get a hit and you get the number of attackers that hit per round. Those that hit hit with all of their attacks, but don't crit on any.

For example, if you need to roll a 15-16 to hit the target, you need 4 attackers to score a hit. Divide the number of attackers by 4 to find out the number that hit.

I don't care for the complete removal of the random element. Removes too much tension if the damage being dealt is just a fixed quantity.



As a DM it seems fair and balanced and I would use it.

This is an edge case, but I think you might need to account for very large numbers of enemies.

For example, if you have 100 dracoliches all attacking a smarmy goodie-goodie paladin, I think they should attack in groups of 10-20 to help ensure the attacks and damage average out. You wouldn't want all 100 to roll a 1 and then the paladin is just sitting there laughing in their skeletal faces.

I'll put it into practice and see how it goes.

I suppose that's a fair point, but the system is really designed to handle lots of weak creatures fighting something stronger, in which case it wouldn't feel wrong, it would feel cool. The paladin walks through a literal sea of skeletons without a scratch.



Presumably they wouldn't all be able to, due to reach and movement.

In that specific example, sure, but consider facing 1000 archers, and arrows to blot out the sun. A player character could conceivably be in range of that many archers at once, and if all 1000 of them attacked in a single unit, yeah it would be far too likely they would all miss. On one hand, there could be an upper limit to how big a unit can get before you split it in two, or three, or four different attack rolls, simply to avoid the loss of verisimilitude of a massive wave of attacks missing entirely. But on the other hand, this is supposed to be epic, and it's epic as **** to see those 1000 arrows land and our hero to stand up again, the ground around him looking like tall grass because of all the arrows in it, and with 200 arrows in his shield and armor but not a single one finding his flesh. I don't necessarily find the risk of complete failure of a combined attack like this to be a problem.