Just as the title says. Assuming I have 1 chief, and n numbers of vegepygmies, how many would be a completely ridiculous number of that such that I should be ashamed as GM.
The rules in the DMG for this seem like complete garbage to me. 10 Vegepygmies would be, according them, "deadly", when the reality is that any sort of AoE spell will likely destroy most of them. Granted, my PCs don't have access to fireball, but even 20 vegepygmies would be a complete cakewalk to a 5th level party which does.
The jump from 4th to 5th level is very substantial, precisely because of things like
fireball. But if the party even at 4th level has access to an AoE
and the vegepygmies cooperatively appear in fireball formation, then, yes, they will be short-lived.
This same party killed (in one encounter): 4 zombies, 8 skeletons, 1 ogre zombie, 3 4th level cultists, and 1 5th level necromancer. Granted, they had assistance with an extra NPC cleric and paladin - and the encounter took basically 5 hours.
And then at the end, the high priest (which didn't attack), turned into a wraith, and created 2 additional spectres. Which they also finished off.
A party of 6 is much different than a party of 4, especially if the extra 2 are a pally and a cleric and you are fighting undead. Was the necro the high priest? If so, you really can't count him in the first wave if he didn't attack. In any case, two waves are a lot easier than the same total creatures all at once.
Same party also killed a CR 11 Efreeti, with a help of a 5th level NPC wizard.
Solo monsters are horribly disadvantaged by the action economy, especially if they don't have legendary actions. And a 5th level wizard is a lot of help. I'm not surprised they killed it, though I would have expected at least a couple PCs to be knocked down in the process.
So yea. 4 Vegepygmies would be over in about 2 rounds, tops.
Even by DMG standards, 4vps + chief is only maybe a medium encounter, so yeah your PCs will not break a sweat.
Basically, you are right, generally the DMG guidelines substantially overestimate encounter difficulty. I think one reason for this though, is that there are a lot of variables that affect difficulty a lot and the table was likely tuned as absolute worst case for the PCs.
- Player expertise is a big factor. It sounds like your crew is fairly capable. Probably calls for at least 1.5x the # of vps right there.
- Do the PCs have magic items? Those generally increase their punch substantially over what is 'expected' for the DMG guidelines.
- What will be the tactical circumstances of the encounter and how will you play the vps? Will they line up in fireball formation to be taken out by an AoE? Opponents who focus fire are a lot more deadly; vps probably are smart enough to do that to any great extent. However, if the vps have any warning of the PCs arrival at all, I'd have at least half of them trying to hide so the PCs may not know initially where or how many there are.
- Do the PCs know about vp regen and how to counter it? This could be a biggie. If they do, then they can mow the vps down; if not, then they are going to keep popping back up.
- Can any of the PCs cast sleep? That will be fairly devastating if a bunch can be caught together since it bypasses the regen ability.
All things considered? Assuming that the PCs don't have too many magic items, and they don't have NPC help, and they don't know about vp regen, and the vps don't line up in fireball formation, and the vps all engage at once (instead of in waves), but do not focus fire, then it seems like maybe 20 should be enough to scare the PCs without killing them. If you don't think that is enough, I think instead of more vps it would be more fun to throw in a thorny or two and maybe a druid-like vp caster who can toss
Charm Person and
Entangle (because it would be flavorful) and maybe a
Cure Wounds for the chief.