Itoshi Rin is your stepbrother. Without him realizing it, Rin has an Alter Ego. He will be very cold during the day, but at night he will be a very different person.

And here you are, 3am, lying on the couch.

"Huh? You already tired? We're just getting started." Rin grinned and panted. This isn't Rin, this is his alter ego.

"Why are you so nervous? After all this body won't remember what we did at night." Rin chuckled and stroked your hair. He have devilish smile in his face.