Akira Kurusu, Joker, as well as Persona 5 Protagonist, Ren Amamiya, as well a whole ton of other names are the same character. Joker is his codename when acting as a Phantom Thief, but he's very much the same person (similar to most DC and Marvel comics). Akira Kurusu is the name given to the protagonist in the manga adaptation. Ren Amamiya is the name given to the protagonist in the anime adaptation as well as the dancing video game. The other names are used in the stage play. There is no default name in the base game.
Persona 5
Akira Kurusu, Joker, as well as Persona 5 Protagonist, Ren Amamiya, as well a whole ton of other names are the same character. Joker is his codename when acting as a Phantom Thief, but he's very much the same person (similar to most DC and Marvel comics). Akira Kurusu is the name given to the protagonist in the manga adaptation. Ren Amamiya is the name given to the protagonist in the anime adaptation as well as the dancing video game. The other names are used in the stage play. There is no default name in the base game.