Arthur Kirkland saw things.
Ever since the first year, everyone at Hogwarts had known that. Arthur Kirkland talked to fairies, to ghosts no one else could see. He wandered the forests and found unicorns, and everyone thought he was weird.
Roderich had witnessed a particular unpleasantness of Arthur in his second year. The French boy had been laughing at Arthur, a good four inches on him, tossing his blond hair. Arthur had stood there, then leapt, fist smashing into the French boy's face.
The boy, Francis, let out a shout and stumbled back. He fumbled for his wand, but Arthur was there, kicking it away, own wand out and pointing at Francis' face. Arthur was scrawny and thin and never paid attention in class, but no one in the hallway doubted Arthur knew the required spell.
Except for the occasional incident, Roderich never had much to do with Arthur. They moved in different circles. Roderich stayed with the Ravenclaws, kept out of the way of the Purebloods who would throw him dirty looks or jinx.
Arthur, as far as Roderich knew, slummed through most of his early years. He terrorized the younger students and snuck illegal muggle items and cigarettes in.
But then, in his fifth year, Roderich walked into his Defense Against the Dark Arts class and Gilbert grinned at him. The boy had been cursed, his hair a bright white, and Roderich hated everything about him. While Arthur terrorized solitarily, Gilbert had his own cronies.
After two weeks of being flicked in the back of the head, Roderich broke.
Arthur was lounging in an abandoned corridor, smoking. He was looking at something that wasn't there, and his head turned sharply when he realized Roderich was standing over him. The Ravenclaw crossed his arms, and Arthur stood up.
"Terribly sorry," Arthur said, and his hand lifted slightly, like he was going to offer a handshake. "Did'you need something?"
"I've heard," Roderich said, picking at a piece of lint on his thin robes, "that you dislike Francis Bonnefoy. It just so happens that one of his friends his annoying me."
There was an awkward silence, and Arthur's hand flicked, like he was swatting away an imaginary toddler. Roderich raised an eyebrow, but didn't say anything. The other boy gazed back evenly, then lifted his chin defiantly.
Roderich watched with a vague curiosity as Arthur faced Gilbert, Antonio, and Francis, fists clenched and wand snapping dangerously. Antonio's wand had been sent flying across the room early on, but the boy was just as dangerous with his fists.
Francis and Gilbert circled slowly, occasionally sending a spell flying toward Arthur. Antonio would dart forward to try for a punch, but Arthur was fending them all off with hardly a snarl.
Roderich hummed and stepped closer. Arthur's head turned as his eyes followed something invisible, and then he caught Roderich's gaze. Arthur's eyes widened, and he faltered, and the three other boys descended.
Roderich sent a card when Arthur was recovering in the Medical Wing.
It was only a week until Arthur came to find him, face still swollen. Roderich watched him approach in his peripheral vision, but he didn't look up from his sheet music. Arthur stopped in front of him, and Roderich almost smiled as Arthur became more and more tense.
"A card?" Arthur's wand was in his hand, but Roderich didn't even reach for his.
"Mm," Roderich agreed.
"I—I—"Arthur struggled with his words.
Roderich looked up, Arthur looked down. Roderich sighed, closing the folder with his notes and musical compositions. "Thank you, Arthur. My classes have been much more peaceful." Roderich examined his nails. "Gilbert was a nuisance."
Arthur didn't make a sound, but Roderich thought he heard something scuttle across the stone floor.
"That's a shit thing to fucking do," Arthur said, and Roderich could tell his teeth were grinding together. "And you were watching and you did nothing."
Roderich glanced up, ever so casually, and Arthur froze. Roderich smiled, because he had the upper hand here; Arthur had a crush on him. And Roderich found relationships tended to fix a lot of problems.