I don't think so. She's probs just a girl who has power and was brought to the palace to be a princess. Just like how it was for the MC and the other princes im her generation.
I thought she might be the high priestess reincarnated
I think it is the high priestess reincarnation. I remember reading the part that Yeon found all of the sharded soul of the high priestess and helped it go to the afterlife then that girl came so yeah.
I even remember the part where she stated that she will give the high priestess a better life, a world of freedom, so she treated that girl as her daughter.
So is it her biological daughter? If so, I think Doha’s the father as she has gold eyes…