Look for auntie ethel in her lair and remember your melee attacks can actually keep enemies alive if you time them right. When fighting her, get her health low without finishing her off and she'll start bargaining, offering that precious hag's eye or even stat boosts if you spare her life. The masked servants around her area respond really well to non-lethal takedowns too, since they're just mind-controlled victims that can be saved once she's dealt with.

Something interesting about those temporarily hostile NPCs like guards or merchants - knocking them out instead of killing them helps preserve your reputation and keeps future interactions open. Just watch out though cause most regular enemies will count as dead for quest purposes even if you use non-lethal attacks, but there are specific moments where it matters like during that high harper stuff in act 3, where keeping someone alive actually changes things up. Pretty much comes down to certain scripted moments rather than being a full system, so pick your non-lethal opportunities carefully when they really count.

Keep an eye on those attack animations since timing matters - you'll want to land those final hits with regular attacks instead of spells or special abilities to make sure you're actually knocking them out instead of killing them. Position yourself close enough for melee but watch your spacing since some enemies have nasty counterattacks even when they're about to go down.