Su Zhe was transformed into the cannon fodder female supporting character in the book. The original protagonist brutally humiliated the sickly villain, and was eventually cut into pieces and fed to wolves!
Su Zhe originally wanted to take advantage of the villain's weakness to kill him, but when she saw Song Yanmu, who was thin and lonely in white and still a hostage that everyone could bully, she shamefully softened her heart.
It's just some help in the dark, but it's crazy.
When Song Yanmu married her and became the regent earlier than in the book, when he became the king who unified the nine states and put his country and himself in front of her...
Su Zhe gradually fell into the arms of the villain.