Um no, he killed the others but he knocks Nakuri out and literally says "i'll get you a medivac" before he picks up Rhaast.
Keelo was after Rhaast, but yeah that was sad.
He was really sweet to Keel in the beginning, pre-Rhaast Kayn was a cool dude. It's nice that Riot is showing he's not evil because I never thought canon Kayn was evil either. The edgy memes are obnoxious.
Rhaast is actually the reason Kayn goes "Anakin Skywalker" so lmao at ur life.