The way this story flows, I'm just more and more convinced a complete separation of species is the best thing for everyone involved. However, it does show that humans are amenable to the most useful of xenos.
If they only had a way of regulating them...
@Kisato : I'm betting he does, but it is just invisible.
@DaylightBlue : Probably the same way your bones eat and drink. I'm betting on him just having a selective invisibility on him that makes everything but his bones invisible. Which is to say if someone tried to touch his face, they could still feel his nose even if they couldn't see it... for instance. A lot of things wouldn't make much sense if he didn't have more of a tangible body than just bones.