LIAM MULCIBER DEMANDS YOUR RESPECT AND YOUR FRIENDSHIP.
Liam is 20, former Slytherin, same as Snape and his lot (who totally need to be in this game, HINT). He's the first Pureblood son of Halfblood (second-cousin!) parents and as such, the world SHOULD be his oyster. It isn't, though, and that's a pretty big problem for Liam here. The world is not shaping up the way he thinks it should be and he's pretty bitter about that. Canon calls his sense of humour "evil" and he really loves Dark Arts, but he is kind of terrified of Dementors so he keeps that in check.
He wanted to be a Hitwizard but was rejected by those idiots in the DMLE, so now he works security and maintenance with the Kenmare Kestrals (who are the best Quidditch team in existence). There is more to learn about him here!