Current working idea is the son of a famed warrior mage (more martial than mage) who himself comes from a long line of such men and women. Despite his many siblings, this boy was the only one to "turn out right" in his father's words. He's always shown great promise from a young age and though he enjoys his position as the clear favorite, always knew his parents' love and support only stayed with him because of his continued success. His siblings are bitterly jealous of him despite his efforts at reconciliation and his parents' words and actions only serve to widen the gap. 

He often grapples with the pride he feels in being the perfect son and the knowledge he is only loved because he is perfect and this often leaves him conflicted about decisions he makes in order to advance himself and his family name.

Magically I'm thinking of a knight or general fighter type who supplements their martial prowess with magic (he's not very good at it so far but just good enough to starve off the ire of his parents). This will also play into the fact that for the first time in his life he's not the best at something, or at least close to number 1.