He is a pervert who desires her so if he couldnt have her as his own he decided to end her.
I'm not that sure but i think it has something to do with Shuli's similar appearance to the late empress
i found a comment somewhere elseee
So the truth is that mfs fell in love at first sight when Shuli and her late husband go to the church to worship or (something like newlyweds do at the church). If you remember the chapter show mfs back full of scars, he tortured himself to forget about her. That asshole becomes obsessed with her and thinks that she was a devil(fucking bastard). Mfs vowed to either have her completely or get rid of her.
The cardinal is twisted asfffff that’s a whole new level of yandere thanks for the replies guys!!
Can someone remind me why the cardinal hate Shuli so much? Like what had she ever done to you girl what