[Xacual]

I highly, highly doubt many of the Sunwoo would side with Sosul over Shioon. Sosul was their princess, but she was not a leader. She also put her authority in Shioon's hands with passing him the medallion. Shioon throughout New Waves has come into that authority and gotten to the point where he has the respect of the entire clan as their leader.

Sosul coming back and trying to reassert her authority wouldn't do so well. Pretty sure she's brainwashed like 9AD though so who knows if she'll even do that, she might not even remember she is the Sunwoo heir.