The Fairy king serves as Toan's guide, awakening him after the destruction of Norune and giving him lessons within Divine Beast Cave and gives Toan a guide just in case he ever forgets a lesson.
He later appears as a merchant selling items within Dark Heaven Castle, while offering to store items. He sells higher tier items, such as premium water, premium chicken, attachments, and gems. He's also the only character in game that sells gems, but only after you reach the castle in the clouds.
The Fairy King, as should be expected from someone bearing the title, is a kindly old man. He is evidently caring and compassionate, as seen by his saving of the towns in Atla and bestowing upon Toan the Atlamillia. He is also extremely helpful, going out of his way to aid Toan many times in his journey.
The Fairy king is an old, short man clad in yellow and red robes and a hat. He wields a staff topped with a blue crystal and sports a gray beard.