What triggers respawns?

[QBob]

I'm still working on the final quest in a Clan Protector world and it's a rough one: there's an Anger Curse and to cure it I need like 20 orc ears from this one tiny level of a tower. I go in every now and then and clear it and get a couple more ears. In the meantime the NPCs are occasionally killing each other.

I guess it'll be fine; unless the last 2 happen to mortally wound each other it should count as a "win", but is there any way I can speed up the respawns here? What triggers them? Time away in-game? Are distance or on/off torches factors?

[Shadow]

Generally it is just time. It will stop if there aren't any quests there.