Zasuke is half human half machine, a cyborg technically.

a laid back and easy-going person, with that being said he is very mischievous as well treating everything like a game, the world is his playground. He was created  as one of the first prototypes to replace humans his task was to observe a certain human and "replace" him. His inability to treat it seriously with urgency extended to him looking for ways to get his mind off of it in different ways...like asking about music groups.