He makes Sirius fight to wrench his wrist away and his hand feels numb with pain after from the force of it. Once they're apart he stands, slow, paying no heed to the blood on his face - nose broken, lip split, bruises blooming - and glaring at Sirius. He smiles coldly and through the near-gore of Sirius's handiwork it looks monstrous. Fitting: if Severus is a monster, then Sirius helped create him. They're part of each other's origins whether they like it or not, and maybe they'd hate each other less if they were less alike. Violent, angry, clever, with childhoods robbed from them by families who hated them. True to form, Severus would hate Sirius even more if he knew.

He raises a hand to his face and a crack noise sounds, a wordless episkey spell setting his head back in order. (As much as it'll go. The end result is only as good as the original state.) Intent stirs around him, almost tangible in the air. If Sirius comes at him again he'll be met with no more patience.

"You don't have to worry."

Severus could snap and bicker back, instigate more - but really. Neither of them wants the company of the other. It's not as if he'll go seeking him out, and it's not like Severus wants this idiot following him around any more than Sirius wants his Slytherin counterpart lurking in his shadows. The only peace between them at any age can be a cease-fire.