Who is Brinker Hadley?

Brinker Hadley is one of Gene's friends, and his main rival for the top academic spot in the class. Brinker is described as rather strange, he makes long-running jokes with rather sinister undertones, seems very independent and determined, and seems like he's his own person. He is the one who starts enlistment fever on campus, and then stops it dead by chickening out since Gene won't go with him. He's a bit of a paradoxical character, and a kind of foil to the rebellious, free-spirited Finny.