Enlarge non-humanoid?

[pawsplay]

Okay so your only chocie is insta kill death magic of some sort then? A troll has fairly good fort saves IIRC.

Also how does an adventuring party starve a troll to death, or suffocate it?

Presumably, if the kingdom is threatened by an army of War Trolls (say, three), the royal wizard should research a spell of suffocation. Other options would be to transport it to an airless plane, keep it locked up for a long time, or beat it down with nonlethal damage, then strangle it. Some poison gases would be suffociation, I imagine. Or you could take it deep underground, then put torches every 20' along the walls and wait for the oxygen supply to run out...

Other ways of dealing with it include save or die spells, transforming it into a bunny, trapping it as long as you practically require, outrunning it, dropping it from such a height it takes a long time to regenerate, turning it to stone, having a Huge summoned creature swallow it, encasing it in stone or resin (which will probbaly also suffocate it), casting "I wish this troll would die," poisoning it (Con damage), bestowing a disease on it, attacking it with wights, or tricking it into becoming an 11th level cleric and becoming a lich, causing it to lose its Con score and consequently, its regeneration.

 

[Nightfall]

I like my idea about the negative energy plane myself...

 

[Sithobi1]

There's always Death by Awesome. Since nonlethal damage doesn't decrease the HP, it can still be unconscious when it has twice its normal HP, and fail the save.

 

[Nightfall]

Yeah but I don't think you can knock a creature with Regn out. At least it turns all non-lethal damage into...nothing I think.

 

[Sithobi1]

Nonlethal damage to a creature with regen is still nonlethal damage. It can be knocked out. Also, you could just swing at it normally.

 

[Nightfall]

Sith,

You say so. It just seemed a little..odd about that. Still I'll accept your word on that issue.

 

[Raylis]

damage that doesn't overcome the creatures regeneration converts to nonleathal damage. My players feared the wartroll until they managed to fight them on their ship, a few chain lightnings later all three trolls were sinking quickly to the bottom of the ocean...