Kiawe's grandfather is a character appearing in Sun & Moon.
Sun & Moon
When Kiawe and Ash were talking late at night, Kiawe said that his Z-Ring was from his grandfather as well as the Charizard. Kiawe conquered the Grand Trial of Olivia to get the Z-Ring. Kiawe remembered his grandfather's words who stated that the flames of the Wela Volcano keep people alive and while they can be terrifying, it still produces the light. He also asked of Kiawe to become a fire-type Pokémon user that grant life rather than destroy it. After hearing his words, Kiawe was determined to master the fire Z-Move and to become the "Wela Volcano".