Technically, it would be easy to put ANY of the bosses on this list from Persona 5, as the entire concept of this game is about making people confess to their horrible crimes - and horrible really is the key word. However, it's opening boss Kamoshida who takes the crown; wielding his authority as a Volleyball coach to manipulate his students, overwork his team, and hog all the glory in the process.
This all pales in comparison to his actions towards female students as it’s revealed that not only does he harass Ann and aim to make her his obedient sex slave (as shown through his internal representation of Princess Ann within his palace), but it’s also implied that the sexually violated one of Ann’s friends Shiho which led to her attempting to commit suicide.
He’s a piece of work, right?
Well don’t worry, because after you utterly destroy his internal representation within the Palace, he will publicly confess to his crimes, acknowledge his actions and then be taken away.
It doesn’t undo the damage, but it stops it - and his career is over.