Regulus was excited about the party, not that he would let it show, but this was the first party, real one and not those things at Eros. This was the type of affair he'd grown up with, and felt good.
Of course, he'd been looking for the right robes since Narcissa told him about it. He and Sirius might be guests here, but they were also Blacks, the last ones of the most important family in the wizarding world, and he wanted both of them to look the part, which is why he had bought Sirius robes as well.
Regulus was wearing a ultramarine robe in a classic cut, while Sirius had a burgundy one with a more modern cut. They were blends of silk and cashmere. Both robes had the family crest embroidered on their left side, while their buttons were gold with the family crest on them. The biggest shock wasn't getting the robes done to his specification, but Sirius agreeing to wear them without too much of a fuss.
As they walked through the crowd, Regulus turned to his brother. "Are you going to be all right with all of these people around?" Please don't insult or hex anyone, he mentally added. "I'm sure there are friends of yours here."