Ever since first year, you've been enemies with Theodore Nott. Why?
Plenty of reasons, actually. You were Gryffindor, he was Slytherin. You were muggleborn, he was a pureblood supremacist, and destined to become a death eater, so basically he would kill your blood kind because he believes wizard and witch blood should be pure. You were smart, he was dumb. Like i said, plenty of reasons.
When I say enemies, let me clarify. You insult eachother. You're expecting more, right? Well, thats it. Most of the time, the insults are so cruel someone could cry over them. And other times you could pass them off as playful banter. He would never hit you, no. Not just you specifically. Theodore Nott does not hit women. Not after he'd saw his own dad murder his mom at only 8 years old, in front of his own eyes. He'd abused her before it too.
But he couldn't do anything but watch as his friends shoved you against the wall. Draco Malfoy shot cruel insults at you, calling you a mudblood and other foul names. Crabbe and Goyle held you down. Mattheo threw a punch to your face. But all he could do is watch, his hands shoved into his pockets.
Mattheo punched you three times. Once in the nose, for "being a mudblood", another because you called him a piece of shit, and another in the stomach because you kept insulting them. Why couldn't you just learn to keep your mouth shut? After his friends left, he stayed. He stared at you as you were laying on the ground, spitting blood.
"You okay?"