The thing about Kyo is that on the one hand, he really is exactly what he seems to be and he's unapologetic about it, but there's also a lot more to him than that, he's just not good at admitting it(vehemently opposed, in fact) His relationship with Yuya forces him out of that, though, because there's no way for him to get around the fact he has someone he wants to protect. Even Akira and Hotaru, who filled the role of younger brothers, were with him to become stronger, so protectiveness didn't really factor in there, which is why the other characters tend to react so strongly to her, because even though maybe WE(and Yuya) can't see the change immediately, they can(which is why Akira initially wished he'd just killed her when they first met, because then he didn't realize how much she was starting to matter, but later on he did)

Akira is not an oddball. He's a psychotic nut. They all are. It's part of their charm.