Been confused about one thing while reading this. In the first place why did mu and her mother allow themselves to be adopted into the su family knowing all the abuse and hardship they were gonna be put though??
power. the Su family is one of the most prominent families of the captial. when they wanted the Mu mother and daughter they would do all they could to get them. plus the used a false premise of being actual blood family so its not adoption but basically returning home. and Yunyao knew if they refused to "return" to the Su, they would be killed. a bargaining chip is useless if its not in your hands. and there is always a danger that someone else will use it instead. they wanted the Mus to control the royals should the need arise since the king is very considerate towards his sister and mama Mu would be the kings niece.
at the time all Yunyao could do was delay and amass power and thats what she did. and the moment circumstances allowed her to leave the Sus safely - she did.
RIP dat ass
Ehhh