3. es, to free Hojung bit they seem to have some kind of plan but what exactly that means is still unknown.
4. Geunseundae is one of the 4 generals. He's the one who convinced the demons to steal and break the mirror centuries ago. Whether Imae is his vessel or not has not been clarified yet but I do think that's possible since it'd explain why Imae's mother reacted the way she did.

1. that black demon was he hiding in imae's body or the black haired boy's body(forgot his name) and when the fight ended with taeryung did he go back into imae's body or the black haired boy's?
2.And does taeryung have the entire mirror not just chards ? Then why are they saying they need to gather the chards shouldn't they get it from taryung?
3.And why did taeryung even want the mirror ? Was it to free hojung?
4.And who is geunseundae ? And is his vessel imae? (Taeryung said he had a vessel and looked at imae)