I think I am going to have to agree that Tasuya is some type of artificial life form. I am not suggesting that he wasn't human at some point in the past, but I think Kraco is correct that he is now some type of "scientific zombie". I think that's as good as a description can be given for now since we don't know if he is a cyborg, AI/robot or other magic creation. The evidence that leads me to believe that he is artificial mostly comes from episode 3, but there have been subtle hints the whole series. In episode 1 Tasuya was concerned about the girl with the glasses observing him because she could possibly discover his "secret". When fighting the ninjutsu master the instructor mentions how if it was simply taijutsu he may not stand a chance. Also through out the initial episodes we have seen Tasuya's extremely proficient use of keyboards with super human dexterity. In episode 3 the girl with the red hair kicked Tatsuya in the leg but she hurt herself instead of hurting him. I feel like this evidence along with the points already covered pretty much suggests Tasuya no longer has a human body.