Arthur is a famous author who writes fantasy novels of adventure and great heroics. His tales may possibly be based on exploits of his own back from when he was a regular Pokémon Trainer, but they might also be embellished, or even entirely fictional, nobody truly knows. For his younger audiences he will dress up as one of the characters from his stories, and read them his books in character.
Elite Four Battle
Concept art for Arthur.
Arthur's name is a reference to King Arthur Pendragon, a heroic figure of British legend, and leader of the Knights of the Round Table. A central figure of British folklore, King Arthur is credited as having defeated many human and supernatural threats, including dragons. Additionally, it is also reminiscent of the word "author".