So fukami actually have mental issue or..?

Wha? You haven't realized?

i just want to confirm he's having mental issue or syndrom or anything.

Yep. He was raped alot in prison and I think he started to like it and hates the fact that he does so he gets angry and is in denial. But it's different with the seme because there are actual feelings involved and I think he was starting to acceptthe sexual urges he has for a man.