Lionel Chang is the son and apprentice of Leonard Powers. Leonard layed his egg in 1961, but since he was 500 at the time, he thought he was "too young for this" so he left the egg to "not be eaten" at a chinese restaurant, where he grew to be 50. Since Lionel is the son of a wizard and thus a wizard himself, he looks like a teenager despite of his age.
He has tried to develop a relationship with Callie Maggotbone ever since he saw her come out of a lake in a revealing bikini outfit.
He speaks with a british accent that he likely gained from his father, but also carries a little Chinese dialect from the Chinese influence he has grown up with. One example of that Chinese influence is that he was yelling for help in that language near the beginning of that episode.