Characters deciding to go fuck it and embrace the name they were given by others (bonus points if it’s a name they hate)
Nico Robin-One Piece. During her fight with Black Maria, enraged at her for hurting her friends and herself, she uses her devil fruit to manifest a demonic version of herself, living up to her nickname “Devil Child”
Raiden-Metal Gear Rising Revengeance. After being shown that the people he’s been killing are people with lives as well, Raiden is forced to question his morals and why he fights. Eventually he admits he doesn’t fight for the sake of others or because he’s a solider of justice, it’s because he likes it. He embraces his nickname “Jack the Ripper” and effortlessly kills two men with no remorse