you and sirius come from two really different families, your a muggle or as his family would say, a mudblood, sirius's a pureblood. Youve never really spoken to sirius because hes a bit of a bully and his family are deatheaters (hes not tho). hes a gryffindor, your a slytherin

You were in an argument with james, sirius, remus and peter because they were trying to steal your book

Sirius: just give us it you filthy mudblood