Grimmauld

Being stuck in an old, grimy house like Grimmauld Place made Sirius irritable and restless, especially when other members of the Order were out there doing their part for the cause.

Not only had isolating Harry been a bad idea, but Dumbledore forcing Sirius Black to stay at Grimmauld Place had only ensured that the man would take off at the first chance.

A classic Victorian top hat can also go nicely with this outfit, and by using certain Conjurations in the Room of Requirement, players can even recreate the look of number 12 Grimmauld Place, the home of the House of Black.

OotP Ch.4 He has a very strained relationship with Sirius, who owns Grimmauld Place and must remain there in hiding.