Cord Van Graff

Son of Artemis and Brandon Van Graff, scion of Hephaestus.
Cord Van Graff first appeared in Season 1.
He was a martial arts champion who fought with Fionn after Fionn had a fight with the Hockey Team. He used a Karate Kid Villain Flying Kick to knock Fionn unconscious.
Son of Brandon Van Graff, employer of Fionn's mother Maria Corvin, Cord was in Fionn's life whether Fionn liked it or not. Fionn had to go to Cord's house for dinner, they had an epic battle in Cord's bathroom that culminated in a knockout brawl on the lawn in full sprinkler coverage. Fionn won that fight and all their subsequent fights, though they were usually very close.
They were a series of Quiet Riots, such as a silent battle in the back of a car, a fight disguised as a drunken conversation in the kitchen of a party, etc.
Cord was initially romantically linked to Mercedes Fabray but became interested in Jenny Swanson, who Fionn was also at that time interested in.
Through all their quiet riots, a grudging mutual respect began to surface and they put aside hostilities, though still tended to refer to each other as buttface, assface, etc.
Cord had himself sent to the Fourth Floor in order to confront Ivan Boyka who he felt was a Communist threat to democracy. Boyka and Cord fought in an abandoned building and Boyka kicked Cord into some rubble that collapsed on him, breaking his back.
Through season 2 Cord regained some use of his legs and eventually even stood, but at the end of season 2 was still bound to a wheelchair for regular getting around.
Cord was Lieutenant of Fionn's Squad in The Tartarus War.
A Scion of Artemis, Cord discovered over time that he was a far better marksman than melee combatant and became one of the snipers for the squad, working in tandem with his mother.