I Have a Catnip Constitution and Met a Yandere Cat Girl in School

The Heroine Is Extremely Yandere, and Then She Is Completely Bad. Don't Have Any Kind Thoughts.

Then the male protagonist should not be merciful, he should only be kind to his family (preferably his younger brother) and the female protagonist, and he will not let bad people die easily, he will torture them, and he has great power.