3 is described in the OP as a mastery, Betelgeuse, and thus having more twos and fewer threes is best (for just-out-of-school characters, at least). And, approaching mastery of the Dark Arts requires [i]live practice[/i]... Meaning having that as a credential necessitates evil. With a two, it's more iffy/gray, but a three, there's no question. This is what I'd recommend: move Duelling (or Transfig) down to two, move Dark Arts down to two, and use the two new points for Alchemy. He would need to be good at Alchemy to do the things he seems to do. If you go for the other character concepts, though, the credentials could be entirely different (you'd need to add wandlore, for instance).