Twelve years old, Dai grew up as the only human on Delmurin island. He gains some fame after defeating a group of fake heroes who had kidnapped his friend Gome. When the Demon King Hadlar is resurrected, the previous hero, Avan, comes to help train him to be the next hero. Dai possesses the ability to gain super strength and a better control of magic when the emblem of the dragon appears on his forehead (or later in the manga on his hand). This strength is because he is the son of the Dragon Knight Baran. Dai managed to learn the Earth and Wave Slashes with Avan, but had to acquire the Sky Slash on his own. Notably, Dai can infuse his weapon with magic (Raidein or Mera) to create more powerful sword techniques, such as Flaming Earth Slash. He can do the same thing with his Draconic Aura, but ordinary weapons cannot take the strain; Hyunckel's Demon Magic Sword breaks after Dai performs a crest-assisted Avan Strash. To suit this ability, Dai acquires an orichalcum sword from the legendary swordsmith Lon Berk, which can take the pressure.