Magnus and Briar
Briar sort of knew who Magnus was. They'd met at a camping thing before, and did go to school together. As much as Briar went to school, anyway, which wasn't nearly as much as Lucas and Paige thought he did. He just didn't see the point in it when he already knew everything he needed from those kind of lessons and the arguments of preparing him for a job one day fell flat when he was already a certified mage.
But knowing who Magnus was, that whatever the boy's powers were and Briar's magic weren't so different, made it easy to go over and sit down beside him.
"You actually know how to play that?" He wouldn't know the difference either way; he wasn't a musical kid.