0range

Finally figured out how it works out! He still appears and can be interacted with, but just shows as 0 HP the whole time. Attacking him again (killing him instantly) causes a game over, at least from the Astral Plane

Yeah I'm really curious to see how it turns out! Mostly just wanted to make sure I wasn't bricking my game by accident and lose several hours of progress, it sounds like he's non-essential though so it'll probably be fine

Nope, or at least I couldn't find his body. The first few times I threw him off it dealt 100ish damage and teleported him back up, but for the final one I think it was angled so he hit an inaccessible chasm/ocean.

~~Weird, I didn't find anyone like that downstairs~~, and hadn't talked to him or anyone else in the building prior to killing him. Not really sure what's going on but I'm going to try continuing from here.

Edit: I found her, and she's acting like I haven't seen him yet. She keeps telling me to go see him.