Npc

Non-Player Character. 😛 It's basically a person that you can't play as, but can encounter in the world.

It's basically a person. 😊 Though it could also be an anthropomorphic animal or Ganon or something like that.

what does he do?

So far as I know, not much of anything. I believe that the NPC was actually removed from 2.10 because it was too buggy.