Tearmoon Teikoku Monogatari: Dantoudai kara Hajimaru, Hime no Tensei Gyakuten Story @comic

In the Tearmoon Empire, Princess Mia was a foul, spoiled, and selfish royal, so it's no wonder she spent years in prison and was ultimately executed. Twelve-year-old Mia wakes up with the memory of a sharp guillotine and a ratty diary beside her, detailing the years she spent in that filthy dungeon—too scary!

Wanting to avoid her unenviable future, Mia decides to reform her image. From now on, she will begrudgingly act like a saint, fix the problems in society before they get out of hand, and even share some of her sweets with others! While others see her as wise and benevolent, Mia knows inside that she is only doing this for herself. But a good deed is a good deed, and so Princess Mia sets out to change her future one step at a time.