Bully's Best Friend

Arabella was the usual dork. Everyone knew it. She knew it. Kids didn't like that she was smart. Because of that, they bullied her.
Her main tormentor was Damen. He was the bad boy of the school and was disliked by everyone. It was surprising he passed every year. Unless the teachers were afraid of him as well.
Then there was Caden. He always stood next to Damen, and never said anything when he was rude to Arabella.
But he was cute. And smart. And funny. When he chose to speak up. He was quiet and timid, it was a surprise he and Damen were such good friends. They seemed to be polar opposites.
Nevertheless, Arabella liked him. He spoke to her, but he was in almost all of her classes. He sometimes gave her pity looks, but never said a word to stop Damen.
So what happens when someone likes their bully's best friend?

Warning: some things will relate to real things the author has gone through.

Thanks to @proffessorfangirl for some input!