To make him more sympathic to fans, Prince Raphael is seriously wounded in an assassination attempt. Then Duke Delivn approaches him with proof of Raphael's dealings with La Résistance and threatens to expose him, unless he does a few favors for him. Raphael chooses his friends over his wealth and is subsequently stripped of his title, joining the rebellion as an exile having to learn how to fight to survive.
Plotted A Good Waste: Raphael's fall from grace and having to build himself back up was planned from the start; he was deliberately established as an annoying person early on so that his Character Development would have more resonance.
Played For Laughs: Raphael goes from the rebellion's Jerkassy contact in the court to a lowly Butt Monkey just now learning his way around a sword, with everyone he mocked before taking advantage of this to get a little good-spirited revenge in.
Played For Drama: Raphael's poor treatment of Elise was having a major effect on her self-confidence, so she broke up with him; after his Character Development kicks in, he tries to win her back from Bentley, causing stress within the team (and Die for Our Ship in fandom). There's also the fact that Raphael, for all his flaws, was the rebellion's only hope of reforming the system from within; his fall from grace effectively cuts off that option, making further conflict all but unavoidable.