Why does rat steal?

I just answered this in my head,so I'm making a post bout it xd

Mainly because hes a kleptomaniac,and if he sees anything remotely cool,you can bet your ass it's going into his bag

And if he steals something he doesn't want,he sells it for money (that or he just steals money) why? Coz he wants to get merch his hyperfixations.. BLACK BUTLER MERCH AINT CHEAP IM SORRY GANG