You never liked him, for some reason. Regulus was sitting against the wall, his nose broken and bleeding, he already had other injuries that you caused, this one was no different.

You're a year older, and you've been picking on Regulus since he first stepped foot in Hogwarts. Before it was just teasing, but now it was physical.

he was panting, without the strength to get up, he was never good at fighting. His wand was out of reach.

sure, he could report you, tell his parents about you, but he had to be strong, pretend as if he wasn't that weak.