I think that Chunwoo and Shioon will fight, and as the fight goes on, Shioon will start to slip into the black origin threshold. Chunwoo will try the whole time to try to talk Shioon out of it, but Shioon won't listen. Then I think that the Murim people, led by Kang, will try to stop him, because they don't want him to follow the same path as Chunwoo, but Shioon won't listen and continues to go after him. Eventually Jinnie wakes up and manages to stop him for a second, and then someone knocks him out while he's off guard. Part 2 ends with Chunwoo escaping. Then I think in part three, Shioon leaves the Sunwoo and tries to hunt down Kaiser on his own, and Chunwoo, Jinnie, Shiho, Sera, Ji-gun, and friends try to bring him back.
Good prediction!
Shioon will be impossible to stop unless someone tries to bring him back, like Jun did when he hugged Shioon.
I really don't know if Shioon will leave the Sunwoo-Clan just like that... Who will take care of it? They've just lost two important figure heads after all.
Whatever Part 3 will be about, I hope it'll be a timeskip of at least a year. I'm dying to see some new designs XD