If he starts with the pm bullshit, fullban him, if he keeps doing it from other accounts, delete any account he makes while saving the webmail in the ban list.
Dont follow the same mistake i was following of thinking i was biased while dealing with someone and end up just not banning that person due to my self perceived biasedness. If you thinking "maybe I am biased" Is all that is keeping you from acting, remember that its natural to dislike someone , no one forces you to like everyone.
Either he acts better and is mature towards whatever situation is around him or he can go take a hike.
Okay, thanks for the advice. I'm going to send him a personal and explain to him that it is just him being moderated. Then he'll probably bring up something about Wild Tengu, but we'll see, I doubt it'll have a different outcome than last time.
Spoiler: What I sent him (click to see content)