Dean Thomas is a Gryffindor student from the same year as Harry. His best friend is Seamus Finnegan.
He is a member the DA, the Spell-Beaking Year and of the second Pride, and he is also the boyfriend of Lindsay Jordan.
He has always thought he was a Muggle-born, though he didn't know his father. During the Spell-Breaking Year, it was discovered he was a halfblood, and later on that his father was Regulus Black. This makes Dean Sirius' nephew, Meghan's cousin and a Black by blood. This enables him and Kreacher to bond. He is also left-handed.