Jinnai D�ko is introduced during The Captain Amagai arc as one of Gy�kaku Kumoi's assassins. He is part of the assassination squad set to caught Rurichiyo Kasumi�ji under Hanza Nukui. He faces off Rukia Kuchiki, and after she refuses to give up Rurichiyo, encases Jinnai in ice but he easily breaks free. In response, he consumes a piece of his Bakk�t� Retsurai and this gives him the ability of shoot blades from his back. Then, he throws Rukia into a building, and temporarily out her of the battle. Then Kenryū confrots him, but Kenryuu's flower ability is only able to keep Jinnai occupied for a short amount of time. When Enryū and Rurichiyo attempt to escape, Jinnai stop them but at this time, Rukia returns to the fight and uses a Kid� spell to protect them. Excited about the battle, Jinnai eats another piece of his weapon and increase his powers once again, making it that much harder for Rukia to keep up with him. He dies in his own attempt to power up further because it causes his weapon to completely consume him. With the battle now over, Rukia approaches Jinnai's bakk�t�, however, before she can reach it, some of Nukui's men retrieve it and carry it off.