A lot of creatures, but not really a swarm or mob

[Herzog]

Several times I have run into the following problem as a DM:
I want to pitch my players against a large group of low-CR opponents instead of one or two high-CR monsters.
Problem is, I'd have to keep track of a lot of creatures, each with very little hitpoints, a low chance to actually hit, but overall a force to be reckoned with as long as the wizard doesn't start lobbing fireballs or something simmilar.

I've used the swarm template in one or two instances, but swarms behave different from regular large groups, in that they 'disperse', and are supposed to be made up of far more creatures then the hitpoints indicate.

I've looked at the mob template, but it isn't that much different from the swarm.

Therefore, I've started thinking about another way to manage large groups of creatures, and here it is:

The Group Template
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1. Attacks. You don't want to roll attacks for every creature in the group. Therefore, the base attack bonus of the group is equal to the base attack bonus of the base creature, +1 for every creature in the group. This bonus represents the possibility of rolling a natural 20 for every creature in the group. If this base attack bonus is hereby increased to or beyond +6, the Group gets iterative attacks. (2 attacks at +6/+1, 3 attacks at +11/+6/+1, etc.)
2. Damage. To account for possible multiple hits, damage is rolled for every point the attack roll exceeded the AC of the defender, with a maximum of the number of creatures in the group.
3. Movement and position. A group can be in the same space as another creature. The creature is considered surrounded, and all attacks made by the group receive a +2 flanking bonus. If the group consists of creatures allowed sneak attack damage when flanking, each damage roll is increased with sneak attack damage. A Group moves at half speed.
4. Size. A group increases with 1 size category for every 'squared' number. (NB: same size at 1 , 1 size increase at 4, another size increase at 9, another size increase at 16) Note that this is exactly the amount of space this number of creatures would occupy when they were evenly spread out.
I does not gain reach from this size increase. It does not need to 'squeeze' unless the space available is smaller than the base creature's size.
5. Armor class, hitpoints and damage effects.
The Armor class of the Group is identical to that of the base creature.
The hitpoints of the Group is identical to that of the base creature multiplied by the number of creatures in the group.
The maximum amount of damage that can be inflicted by a single hit is the number of hitpoints of the base creature. However, when this amount of damage is inflicted by a single attack, the number of creatures in the group is diminished by one, directly influencing it's base attack bonus, damage, and possibly size. When the attacker has the Cleave or Greater Cleave feat, it can make additional attacks whenever its attack reduced the number of creatures in the group as is normal for the feat in question.
When an attack does less damage than the number of hitpoints of the base creature, the damage is taken from the total amount of hitpoints of the Group.
6. Area attacks, splash weapons and saving throws
Area attacks that do damage to each individual in the area do damage as normal. That is, the damage is applied to each individual the group is made up of. (effectively multiplying the base damage with the number of creatures in the group.) Splash weapons do double damage, as if hitting two targets. If the damage applied to a single individual in the group exceeds the base creature's hitpoints, the number of creatures in the group is reduced by the number of creatures effected. If only part of the group is affected by an area attack, The maximum number of creatures affected is taken as a percentage of the remaining creatures identical to the percentage of the group's area that is affected.
The Group's saving throws are identical to that of the base creature. This represents the balance between automatic successes and failures on saving throws.
7. Ability damage, ability drain, and level drain.
The group is unaffected by ability damage, ability drain, and level drain, unless a single attack can damage and/or drain enough to render the base creature helpless or dead.
8. Grapple.
You can not grapple a group. However, a Group can attempt to Grapple you.
For Grapple purposes, the Grapple check for the Group composed of the base attack bonus as explained under 1, and the size modifier of the base creature(s).
9. Death.
When the number of creatures in the group is reduced to 3 or less, they stop being a group and become single creatures. The number of hitpoints left in the group is spread evenly over the remaining creatures.
When the number of hitpoints of the group drops below 3 times the base creature's hitpoints, consider the group reduced to 3 creatures.
When the number of hitpoints in the group drops below 0, all creatures in the group are dead or dieing.

So, what do you think. Did I miss something? Do you feel there is something wrong with it? Please comment.

Herzog

 

[lottrbacchus]

When I have a large number of low hp baddies, I use a six-sided die showing the number 1 for each. If one gets hit, I flip it to 6 if the damage isn't enough to take it out.

I have enough d20s to roll for lots of creatures at once.

 

[Bladesong]

Personally I would just use "mook" or "minion" rules, but your method would probably work.
I am not sure I understand your damage system. It seems the easiest thing to do would be to roll the regular damage of 1 creature in the group and add 1 point of damage for each additional creature in the group up to half (not every creature in the group will hit every character in the group). So if there were 10 goblins and they normally inflicted 1d6 + 1, I would say a group hit is 1d6 + 1 + 5. Otherwise I would say try it, it will probably work.

 

[Scurvy_Platypus]

If you really like it, go for it.

It seems kinda complicated to me, and I'd simply go with Mook rules myself.

You can find a couple of approaches in this thread:
http://www.enworld.org/forum/showthread.php?t=208523

I think the rules that Psion linked to would do just fine for the sort of situation you seem to be trying to address.

Tonguez has a pretty good suggestion too. His suggestion tends to work out a bit better for a smaller "discrete" group of mooks. I've found that this approach also works _really_ nicely for doing a "minion" or "mook" version of a bigger or nastier critter.

 

[Kerrick]

I've used the swarm template in one or two instances, but swarms behave different from regular large groups, in that they 'disperse', and are supposed to be made up of far more creatures then the hitpoints indicate.

There's a reason for this:

However, when this amount of damage is inflicted by a single attack, the number of creatures in the group is diminished by one, directly influencing it's base attack bonus, damage, and possibly size.

Imagine having to recalculate BAB, saves, damage, and stats (if size decreases) on the fly, in the middle of combat. I can almost guarantee you won't do it more than once.

Swarms are specifically designed to have more numbers than their HD/hp indicate because you don't kill them all - you "kill" the core, which represents the largest/most aggressive members of the swarm, the ones keeping it together. Once you eliminate those, the rest will lose their drive and disperse. The same concept applies for mobs - if you kill enough members, the rest will finally realize that it's in their best interest to go somewhere else.

If you're interested, I reverse-engineered the swarm stats and made a template for it.

 

[Herzog]

@lottrbacchus:
this Group template is not only meant for low hp creatures, but also for high-hp creatures in large groups. (with high-hp I mean creatures that will not go down after 1, or even 2 hits.)

@bladesong: you're right, the damage rule didn't sit right with me either. I don't want to use the auto-hit rules for swarms, but a generic dmg bonus equal to half the number of creatures in the group sounds good.

@Scurvy_Platypus:
I read some of the comments in that thread, and so far still like my system better. Also, the link by Psion is to the front page of some website, and I couldn't find the article in question.

@Kerrick:
I know the reasoning behind the way a swarm and mob work.
I just want an alternative to handle large groups that don't act like a swarm or mob.
One of the things that always bothers me about swarms is that they avoid the normal rules.
What happens if someone with the cleave feat hits a swarm? according to the feat, if he kills a creature, he may hit again. Having hit the swarm would definately mean he has killed several of the creatures in it. However, since the swarm is considered to be a single creature, this doesn't apply.
What if you cast a spell that does 1 point of damage to each creature in the area, with no number of creatures limit? how many hitpoints does each individual creature of the swarm have? or is the swarm (again) counted as a single creature? Area effects do extra damage. A fireball should inflict at least 1 point of damage to every single insect in an insect swarm, but the swarm somehow survives because it is treated as a single creature.....

Now, I can handle that for 'real' swarms, but if I want a way to handle multiple opponents in a more structured way, I'm definately not going to use the swarm template.

Which reminds me: has anyone determined the dmg and CR of a swarm of stirges yet?

 

[Kerrick]

I just want an alternative to handle large groups that don't act like a swarm or mob.

That's cool. I think what you're looking for is something along the lines of the mass combat rules, where each unit is treated as a single creature. Check this out and let me know what you think - it's a revision I made of Mongoose's OMCS.

One of the things that always bothers me about swarms is that they avoid the normal rules.
What happens if someone with the cleave feat hits a swarm? according to the feat, if he kills a creature, he may hit again. Having hit the swarm would definately mean he has killed several of the creatures in it. However, since the swarm is considered to be a single creature, this doesn't apply.

As opposed to him getting near-inifinite attacks against the thousands of creatures in his reach? I'd say making the swarm a single creature is infinitely more logical in this case.

What if you cast a spell that does 1 point of damage to each creature in the area, with no number of creatures limit? how many hitpoints does each individual creature of the swarm have? or is the swarm (again) counted as a single creature?

It's a single creature, of course. It would really depend on the area. And who would make a spell like that anyway?

Area effects do extra damage. A fireball should inflict at least 1 point of damage to every single insect in an insect swarm, but the swarm somehow survives because it is treated as a single creature.....

A swarm also occupies an area greater than that of the fireball's radius. Logically, though, dropping a fireball into the middle of a swarm would decimate it to the point where it would disperse, no matter how much damage the fireball did or how many hit points the swarm had, unless it's something like a hellwasp swarm.

Which reminds me: has anyone determined the dmg and CR of a swarm of stirges yet?

3d6 + blood drain, CR 10. You can find the full stats here.