Red X good guy или bad guy???

I can't really answer this. He's kind of both. He's fought the Titans before, but he's saved them too.
He's kind of in-between:)

Anti-hero.

He's a little of both, a few times he's quoted to saying, "Mine." as an answer to the question, "Who's side are Ты on?"

So, according to him whatever side he feels like being on. Personally, I count him as a criminal.