Why is it whenever I try to find any info out about this game I find posts full of edgy "haha I killed that, are U mad?" assholes and borderline "race realists"?
Ffs I just wanted to find a post that would help me avoid killing Kobolds and the one posts I find asking the question is full of edgelords bragging about how they love to kill "vermin" races and gays.
This is what you get when you make a fantasy world were certain races are born evil, it attracts all the racist freaks that want to live out their genocide fantasies.
It's killing my fun for this game.
Some plot important characters do show up later if you do opt to go for non-lethal. Enemies you will not see again won't. The arrogant white dude at the start of the game will, for example, show up later if you choose to knock him out vs outright kill him. The method for recruiting the evil origin companion involves non-lethal. Some of the allies you can choose to betray may show up in Act 3 depending on whether or not you choose to non-lethal vs kill.
Also, certain items that you can only obtain from killing someone will not appear if you only knock them out. Also relevant, when the plot does actually require you to kill (as opposed to stop, subdue, etc) someone, knocking out doesn't fulfill the criteria.