Akutoku Joou no Kokoroe

In a world of royalty and magic, a young Japanese woman is reincarnated as Princess Luxeria. But the princess is born with magical abilities so strong and terrible that she agrees to live her life locked away in a tower. When her family is betrayed and her royal parents are murdered, she's forced to step out of her self-imposed exile and into a treacherous world. Princess Luxeria must pretend to be the perfect puppet ruler... all while concealing her burning desire for vengeance.

(Source: Seven Sees Entertainment)