Crafting appropriate combat encounters for large groups

[Asmor]

D&D 3.x is heavily balanced with a 4-man party in mind. Going significantly over this number creates some interesting problems for combat encounters; you obviosuly can't throw a CR 4 at a party of eight 4th-level characters and expect the same challenege you'd get from a party of four 4th-level characters. Less intuitively, however, is that you can't just toss commensurately higher CR critters at them... Something 3 or 4 CRs higher than the average party level will often have something-- whether a high AC, powerful attack, or nasty saving throw-- which will rip any number of people too low for the challenge to shreds.

The best option, I think, is to just throw more things at them. I don't know exactly how you should work it out, but if you've got an 8-player party I think it should be sufficient to take an appropriate challenge for a 4-player party and double it. 5 zombies? 10 zombies! A harpoon spider? 2 harpoon spiders! Etc. Obviously, when the chance arises you should try to modulate the makeup a little to add some variety to the combat. In the latter case for example, sure, you could just throw 2 harpoon spiders at them... But instead, you could change one of the harpoon spiders into an ettercap and a 1st-level drow warrior.

But this presents a unique problem... If you're always doubling encounters, then how do you get an encounter with a single creature? I'm not saying single-critter encounters are always good-- in fact, they usually suck compared to fighting a group-- but sometimes for whatever reason you really want to or it's a good idea or whatever...

So how can you adjust a single critter to be an appropriate challenge without ramping it up to the point where it can rip the party to shreds? I can think of two options... Up the HP, or increase the actions. Hell, possibly both.

The first is the simplest, and also sort of stays within the confines of the D&D rules set. Just double its HP. In theory, this should double its staying power.

The other option requires that you be comfortable with screwing with the rules a little... Have the baddie roll initiative twice, or just let it roll once and then it gets a second set of actions at 10 counts lower. One of the biggest hurdles a single creature faces is the severe deficit in number of actions it gets.

So what do you all think? Any insights in running combats for large groups?

 

[balterkn]

IME... your point about raising the CR is very valid. Multiple groups with more than 4 PCs that I've worked with find they can only barely hit the creature (17+ for the main fighter), while 2 or even 3 of the matched (CR equals average party level) tends to be most balanced.

In this case, individual powers, by either CR or ECL, have the plus or minus 4 levels in mind for being able to potentially overcome encounters. If designing an encounter for 4 characters at ECL 6, a CR 9 should be winnable but very difficult. However, even with 8 characters ECL 6, a CR 11 creature is likely to be able to do a TPK without much problem (a single wizard 11 will have spells that can slaughter 6th level characters and have enought wealth to have equipment to give some staying power ot other advantages completely out of range of the party's wealth).

So, where does this leave us? You analogy of using more is good, but maybe the BBEG needs more minions to keep the 8 characters at bay, while remaining at a reasonable CR for the ECL average of the party. Thus, don't just double everyone, but add more mooks, so that the swarm of PCs aren't able to use their number to their advantage. Alternately, you can also use terrain to limit the PCs ability to bring all their characters to bear at once (limiting an enemy's ability to maneuver is a central military tactic - the bad guys should use this tactic, especially against large groups)

 

[nittanytbone]

Build your BBEG to be capable of getting multiple actions.

- Summon critters to his aid, so they can take actions on his behalf
- Use Timestop (perhaps from a charged item) or a Wish (from an item as well) to get an extra action or two
- Use an AoO area-control build for a melee type
- Use quickened spells to get more actions.

For example:

Round 1 - BBEG Cleric casts Summon Monster spell, choosing to get 1d3 or 1d4+1 weaker monsters. These critters make a front line for him to hide behind.
Round 2 - BBEG Cleric casts Animate Dead then follows up with Quickened Bless (free action) to buff all of his mooks at once.
Round 3 - BBEG casts Quickened Divine Favor and then follows with Divine Power, or continues buffing from the back rank (Prayer, Pro Good, etc), or throws attack spells.
Round 4 - BBEG wades into melee or keeps slinging spells.

Even a low level BBEG could use Divine Metamagic or Swift spells to get Free Actions and thus more spells.

Also, having buffs running before the fight is very helpful. 10 min/level buffs could quite reasonably be running, as could 1 hour/level buffs. Having Vigor running during the fight gives the BBEG staying power too.

Don't worry about tying up higher level spell slots with Quickened Spells or Extended Buffs, either: A high level caster vs. a party needs lots of spells in a hurry. They almost certainly will not run out of magic before they die. A Quickened True Strike that gets fired off and used is more helpful than a Chain Lightning that never got cast.

 

[Dracandross]

Id like to point out that increasing number of 8man just twice isn't most likely enough. As they have more people they have enough crew to fill slots that are needed just once like trapfinder&disarmer. That will leave more room for supporting chars like druid/bard/marshal/whatever or more sorcs with enormous amount of spells with area capacity. Id say that its at least 2.5times 4man effectiveness if party is somewhat balanced.

Of course increasing numbers make surrounding and flanking alot easier so that might not be such easy way to find it out. Id prolly go for less with more Hp

Also experienceflow is then more than compared to 4man and that should slightly be reduced to stay in same advancerate.

-Dracandross

 

[Stormrunner]

Remember that an 8-member party doesn't just inflict 2x the damage of a 4-member party - they have 2x the number of actions per round. This makes a big difference: an 8-PC party is more of a threat than a 4-PC party that deals double damage. They can cast more spells per round, which means more/faster buffing for the party, and more saving throws for your monster. They can flank easier. They can have a bard hang back, singing and buffing, without weakening their front line appreciably. The meatshields can form a nice defensive circle around the casters.

Doubling the number of monsters helps nullify this problem, and is generally good (though it makes more work for the DM, and combats will take longer, real-time). For a lone monster, just doubling its HP isn't really enough. It needs a higher AC and better saving throws. Try doubling its HD and using the advancement rules. Give it "elite" stats, or a class level or two.

 

[Someone]

The best option, I think, is to just throw more things at them. I don't know exactly how you should work it out, but if you've got an 8-player party I think it should be sufficient to take an appropriate challenge for a 4-player party and double it. 5 zombies? 10 zombies! A harpoon spider? 2 harpoon spiders! Etc.

Even this have problems if the party has any grasp of tactics, as they'll concentrate on one opponent and kill it before it can say "fried fish" and render the opposition much weaker. In terms of action, it's somewhow like if the lone CR 4 opponent for the 4 party member suddendly was slowed any time he drops below 1/2 hit points. You may want to use tougher monsters, not only more monsters - how much tough they must be it's more an art than a science to determine.

If you're going to use a BBEG, have in mind that he can have double the number of magic items than a regular BBEG without breaking the wealth-per-level guidelines.

 

[FEADIN]

At low level you can increase the number by 1.5, and give max hp to all, at mid level you can keep the 1.5 for the mooks, the hp max and add a follower/apprentice with the boss, 2 to 4 levels lower.
At high level it depends more on the capacities of the group but the follower/apprentice with some special "elite guards" is a good way to go.

 

[nittanytbone]

Another option could be to switch from a totally pre-planned campaign to a more old-school site-based campaign. Just create a locale or game world that exists semi-independently of the PCs. Generate monster encounters by using the "commonly encountered" guidelines in the MM and random encounter tables.

If the PCs think they can handle a whole tribe of goblins, well, they are free to try. There will be more treasure and XP for them if they can. If they restrain themselves to killing off small patrols and such, its safer but less lucrative. So long as you allow them to gather good intel on the threats and make the threats somewhat reasonable and predictable (i.e. not throwing in a level 20 goblin monk or something crazy among the rest of these level 1 warrior goblins and the commoner female types) it should work.

The classic module B2 "Keep on the Borderlands" is a good example of this kind of adventure. It lets the players balance the risks and rewards. Expect character death if they are foolish, but hopefully not a TPK.

 

[pawsplay]

I usually just take an appropriate EL encounter for their average level, the add also a boss monster of that CR. You have more creatures, but you also get something that requires them to work a bit harder to take down. It also allows specialists like monks or trippers to shine.

 

[Nifft]

Non-Affiliated Class Levels.

Don't throw them against a Fire Giant Fighter. Throw them against a Fire Giant Monk. It will have better defenses, and will be a bit unexpected.

Don't throw them against a Nymph Druid. Throw them against a Nymph Barbarian.

Same with a Naga Sorcerer vs. a Naga Fighter.

Basically, trade hitting power (which kills PCs) for staying power (which lengthens fights).

Cheers, -- N