Kabuto is a foundling. He was found on the street when he was very young by a kind family that took him in, then found him a place as a palace servant. He's glad to have been found, though he feels no familial affection to those that helped him. It's not a bad life in the castle, either, but a homeless orphan will never be able to climb the social ladder or achieve the learning he wishes to. He has very little memory of his life before he was found, but figures indulging the mild curiosity and attempting to find out his origins wouldn't do him any good. His focus is on where he is now, and what he can do to improve his chances for the future.
Kabuto's polite demeanor and talent for smooth efficiency have gained him the respect of the head of the butlers and the maids. He treats everyone with respect and kindness, and seems to have several friends among all of the palace's many occupants, social class notwithstanding.
Though very detail oriented and conscientious about performing his duties, Kabuto has a different dream. He has discovered a talent with magic. Specifically, the ability to convince people do do what he wants them to, even think what he wants them to think. Despite the thrill he gets using this edge on unsuspecting fellow servants and the occasional nobleman, he hungers to know more about how humans work. Not just mentally, but physically as well.
Living in the palace has been both a gift and a curse. Knowing the Queen is an oracle, and well versed in the magic of life and death draws him, but she hasn't taken a student in as long as he'd known her. He's also not so foolish as to attempt to sway her with his other skills, nor has he had the opportunity to present himself to her.