Ok let me paint this picture for you and try it on for size if you will. He is the "heir apparent" to take his fathers place in the kingdom. He at some point in the future feels he is now ready to ascend to the position of responsibility. His father doesn't relent his position at a time of Adolins liking. He starts to breed discontent. Among the plateholders and bladesman he is in the top tier of ability who is often relied upon when duty calls to preform when needed that is above and beyond (kinda like a champion eh?). He looks around and all his family becoming a radiant and he isn't (breeds contempt/jealousy). Due to events like the chasm and more than likely more TBD he sees his betrothed form a close bond of friendship with Kaladrin (more jealousy). A event happens that he catches at the end of between the before mentioned two and catches a "friendly" hug or embrace that sparks even more along with the above mentioned points. He feels that he is betrayed by those closest to him.
He already has committed a killing with anger and malice (ie hate) taking out Sabwhatever opening a "doorway" if you will to Odium. He is a close and trusted member of his foes (odiums) so he is tactically a good person to invest in to turn to gain access to the inner workings of the new Knights Radiant. But since he is not in it, he flies below the radar. Also it is highly likely that events will be taken to break down the trust of the orders (traitor within the ranks) in regards to the public by Odium's assets to divert there attention (misdirection look here fools not there). The "writings on the wall" if you will teehee :).
Cool points will be awarded to those that catch that reference if you will.