If it helps, Fu was suffering quite a bit from her own evil actions. She convinced herself that she had to do them for her father's sake, but deep down, she knew how wrong they were and how horrible of a person doing them made her. She's not like Yotsu's mom who can ruin people's lives without a shred of remorse.
No. You're ASSUMING that she felt remorse. Show me a single panel where that bitch felt a single shred of remorse. She didn't at all. Rather, she was fine even involving those who had nothing to do with her father or his affair or his unclimatic suicide.
She was fine blackmailing adults, just like yotsuha's crazy mom. If anything, the plot actually showed us that she's the one who took over that crazy mom's place, after mitsuha killed that psycho. She was doing the exact same thing. Only difference is she was using blackmail and brains while the other one used manipulation and her beauty.
I bet she'd wish that that crazy mom was her's instead of yotsuha's. But anyway, in a way, she really did become the person that her father was seeing her as while he was coping with his nonsense, instead of her, idk, trying to get along with her own naive mother or her mother trying to do the same?
And as for having any regrets or remorse, please 😒. Bitch knew she was gonna get confronted by those 2 in that restaurant and what did she do? Set up a whole freaking stage, with an audience, filled with unknown people that we could care less about, to play the victim. "Feel bad for me. Me. ME! YES, I DO LOOK DOWN UPON ANYBODY, LIKE THEY ARE ALL INSECTS (just like the crazy mom) BUT ANYWAY I'M THE VICTIM! LIKE LOOK AT ME, I EVEN HAD TO UNDO MY PIGTAILS JUST TO BE DRAMATIC AND SHOW MY TRAUMA 🥺"
The only consequence I remember, this bitch faced cuz of all of these bullshit she pulled up or maybe because of dealing with her father's bs was her having to take multiple medicines cuz she had heart issues or something, just like yotsuha (but yeah, the plot sure quickly dismissed that for whatever reason).