i think seoho betrayed him as an act of maybe saving him from something bihwan wasnt aware of, or maybe some consequences to come and so seoho sacrificed himself and restrained bihwan somewhere so he wouldnt be able to intervene. plus, seoho wouldnt have said “find me” or wtv if he genuinely hated bihwan and locked him away for what was like eternity for no reason
Lowkey I think Seoho died after sealing him away. Because Seoho did say "wait for me" so the only thing I can think of is that Seoho died or was captured shortly after that. Seeing as how they were going against the king and they knew it would be dangerous for them. But then again I don't know why Seoho would have to seal away in the first place
He looked so sad in the mirror I wonder why seoho betrayed him, or were we already told and I just missed it