You'll talk to him briefly and then your adventures resume.
You'll appear back in the cell with Vernon Roche. Otherwise, talking him into a surrender prevents you from needing to battle against him at all. You need to be ready to block his sword strokes, then retaliate with some blows of your own. If you go with the violent options, know that Aryan is a capable swordsman.
We recommend pushing for a surrender again (the top option). Go with the latter option and you'll come to a three-way menu where you can again suggest surrender, or battle against Aryan alone, or battle him and his men. You can initially choose either to fight or to offer him the chance at surrender. You have options about how you want to proceed, and those options will affect a coming point in the game. You don't necessarily have to go straight into a battle, though. When you reach the top floor on the tower, you'll find yourself facing Aryan. Then climb up the tower, battling a handful of soldiers as you ascend. Make a quick run of it to reach the base of the tower, where you're safe from arrows. He is surrounded by archers who will pick you apart with arrow shots if you let them, but you really have no choice you must proceed forward.
Aryan La Valette calls down at you and the king from atop a nearby tower.
