Gladion is a male Pokémon trainer and the son of Lusamine and Mohn. He serves as the acting president of the Aether Foundation after his mother's defeat. Initially appearing aggressive and confrontational, Gladion is deeply protective of his sister Lillie and the Pokémon Cosmog. Throughout his journey, he forms a friendly rivalry with the player character Selene and works to reform the Aether Foundation. Gladion is skilled in battle and uses a Type: Null Pokémon. He expresses gratitude toward those who help his family, particularly Selene, and takes pride in his sister's happiness and personal growth. His character arc shows his transformation from a troubled youth into a responsible leader dedicated to protecting his loved ones.