I have absolutely no understanding of the Rokuhara Tandai hierarchy. South refers to himself as the leader when his official position is representative and Kakucho is the president. But Kakucho has no real power in making decisions regarding the gang. It makes no sense
What if Sanzu becomes obsessed with his lover and that is why he's one of the worst bfs... He'd definitely bring justice to whomever hurt his loved one in a very creepy way (like that present to Mucho).
He can't show his affection properly and he just wants to be loved damn