...Don't judge me but...I don't remember who that is. :x So I might have killed him or maybe not lol.
It's one of the best quests and characters in the entire game. O:
Knowing that you rush so fast through games, I bet you didn't even talk to him before you wiped out all the bandit camps, lol.
Nil hides next to the bandit camps, planning to wipe them by himself, and normally you would at least notice him once while sneaking around the camps, looking for an opening. Talking to him starts the quest line, which spans over the whole game.
He's...very weird and kind of a psychopath, lol, but that imo makes Nil so interesting and likable. At the end of the quest line you can actually fight and kill him...
I get that many choose to fight him and ultimately kill him, because he seems really untrustworthy and the last time you meet him like a total creep, that set you a trap. But if you choose to trust him instead and not to fight, he will actually listen and you have a new friend/ally, who will also assist you in the end battle.