...

Or is he?

It seems like you might be joking but I'll say this anyway, he assaulted him, penetrated him with items, sexually touched an unwilling person, all of which can't be done on accident. Good people, hell, OKAY people don't do this stuff. Who cares that he's starting to feel bad because he just realized raping Shou wasn't as fun as he thought it was going to be. If it takes assaulting somebody to find out rape is bad then you do not have a damn conscience. Your conscience stops you from doing that shit. Also Harada makes it pretty clear that Fuku isn't against raping him, its that he couldn't get hard seeing a tortured and broken person in front of him. If he hadn't taken off the blindfold or seen his face Fuku wouldn't have felt bad or stopped. He didn't feel bad for raping him. He felt bad because it didn't go how he wanted and he didn't feel how he thought he would feel.

I doubt there was any ounce of guilt or conscience there. There was only disappoinment and shock that his plans and expectations did not go how he imagined them to be. Total psychopathic behavior. Cute the OP thought Fuku had any.

I don’t think you’ve said anything wrong... Fuku seemed to have felt something like pain, seeing Sho’s sorrowful disheveled face, and that’s a little bit of change. I want to believe that that’s a sign of conscience, because until then Fuku only felt pleasure in seeing Sho cry, but now he seems to be regretting what he did and feeling bad about going through with his plan. At least he doesn’t find pleasure in troubling Sho at the moment.

I don’t think people should fire at you about whether or not Fuku has conscience though. Obviously your point was not to debate.