We don't know where Tachyon came from. He came in one day, sat on the sofa, and refused to leave.

He's very catlike, only letting himself be pet when he  decides it's petting time. He hates being held with the fire of a thousand suns. He's the most attached to Abby, being rather protective of her, though he also likes to lay on Miku--probably because her servos and processors are warm.

None. If you place any clothes on him, he will rip it off with claws and teeth before you can even snap a picture for Instagram.

Chewing on things he shouldn't.