Houfuku Saimin

A prestigious private girls' academy where daughters from good families gather.
The protagonist's parents, who once ran a small company, were driven into a corner and committed suicide, leaving behind only a small amount of money.
After overcoming various hardships, the protagonist became a teacher at the academy.
While looking after admiring students (Heroine A) and a handful but adorable pupil (Heroine B), the protagonist felt that becoming a teacher was worthwhile.
However, they discover that among their students is the daughter of the company that drove their parents to death.
Bitter memories from the past resurface.
The protagonist can no longer suppress the dark desire for revenge welling up inside.
"I won't kill her. That wouldn't be revenge. I'll humiliate her, corrupt her, and make her regret it for the rest of her life."
Having obtained the power of hypnosis, the protagonist begins their revenge.