Dire Situation [1]
After Hestia came Yiren, and after Yiren came Darius.
They were both fighters, so they received the same treatment as Dominic. It didn't end well for either of them.
Yiren was relatively skilled for her age. There was a reason for her arrogance.
Not only did she have good control and understanding of her laws, but she'd also been going in and out of the palace to experience the outside world far more than her siblings, so her practicality and instincts during battle were leagues above her peers.
However, even she had weaknesses. They, of course, weren't to the level that they betrayed Damien's expectations, but Damien was planning to turn Void Palace into something magisterial.
It was only natural for him to bring his siblings past their current level.
Yiren's problems were more mental.