Two different things.

Steiner comes from one of my favorite animes, Steins;Gate. Thule comes from an older video game where one of the deitys/religions was Cazic Thule who as a deity was the god of the plane of fear. So I felt at the time that since I was totally controlled by my anxieties that it was suitable.

I'm a little better now but at times it comes lurking.

I also thought it sounded cool too.