After Rista and Seiya retreat once again to the Divine Realm, Aria proposes that Seiya train under the tutelage of one of the Gods there. A looming crisis on Gaeabrande compels the pair to return, and seek out companions to aid them in their quest.

Following Mash's recovery, Seiya agrees to allow him and Elulu join them on the adventure, but insists that they receive more training first. The pair offer to lead the party to a cave called the Dragons' Den, said to contain an ultimate weapon.

A delegation of Roseguard Imperial Knights summons Seiya and the others to a nearby fortress, where a wing of demon houseflies is attacking from the air. Seiya offers his help, but when he butts heads with the knights' leader, things turn ugly.

Kilkapul summons a nightmarish reaper to eliminate Seiya and the others, and not even retreating to the Divine Realm is enough to stop its advance. After Mash and Elulu improve their skills, Rista resolves to step up her own game, as well.

Rista narrates a retrospective of the major events of the first half of her adventures with Seiya, Mash, and Elulu.

In violation of Divine Realm law, Rista opens a portal directly to the location of the final boss fight, where Seiya and the Demon Lord are locked in mortal combat. Seiya resolves himself to make the ultimate sacrifice to defeat the Demon Lord.