"You don't need me," Snape said. "And I certainly don't need you. I don't need your dear Remus either but he is the one who came to me--he does need me and at least he knows it."

Black was an arrogant bastard the same as he ever was.

"What are you going to do--curse me?" Can't do anything on the grounds, Snape knew it. Did not react and did not want to fight. He needed to keep this position so that he could remain on the grounds where he would be safe.

"I'll stay away from Lupin unless he comes to me. And he will--we had an agreement." Let Black ask Lupin about it because Severus was not interested in explaining if Black was too stupid to understand.