Long story short, we found out he was a sockpuppet of a user who got banned here a long time ago, TabuuandPeach. I can't link his profile directly as it's not available but here is one of his posts in a thread.
The funny thing about this lore is that we didn't use our fancy IP check powers or anything. He literally just admitted it in his user page across NIWA wikis and his forum profile.