While searching through their school's library, students Jin, Akira, and Rena discover a demon encyclopedia originally owned by the Ahriman Occult. Rena explains that demons coexist with humans in a world called Valhalla, then takes notice of an incantation written in the encyclopedia. As the three students recite the incantation, a girl named Ami summons them to a desolate Valhalla. Ami pleads for Jin and Akira, whom she claims are the Son of Light and Prince of Darkness, to save Valhalla with their latent abilities, as the world was torn by the desires of mankind and demons. Malicious Gargoyles suddenly appear and attempt to take special artifacts from Ami, until Jin and Akira fight back using gun-like Devilisers to summon the demons Rand and Gale. Their powers awakened, Jin, Akira, Rena, and Ami embark on a journey to save Valhalla from annihilation and find a way back home.
Jin, Akira, and Rena happen upon a book of demons in their school's library, which also tells of a world called Valhalla. Chanting a spell, the three are beckoned by Ami Kashihara to Valhalla, devoid of life, where Jin and Akira realize their true natures as the Son of Light and Prince of Dark. Joined by demons Rand and Gale, the group set off to find a way to restore Valhalla.
2
"時の鎖"
"Time Chain"
October 12, 2002
3
"バルバトスの要塞"
"Fortress of Barbatos"
October 19, 2002
4
"ハボリムの陰謀"
"The Harborim Conspiracy"
October 26, 2002
As the team proceed to Flower Town, where a time chain is supposedly located, a demon of the Imperial Army named Harborim commences a pursuit against them. Meanwhile, Rena bickers with Jin about being dragged into this journey against her will, and that unlike him and Akira, she is not a Devil Child. Finding a phony time chain along the way, the team are lead to a chain market, but their search is for naught. Returning to the market the next day, Harborim holds Rena hostage, revealing the market to have been a set-up. Jin and Akira manage to defeat Harborim and claim his ring, which turns out to be a piece of a time chain.
5
"海をつらぬけ!"
"Pierce the Seas!"
November 2, 2002
6
"いやしのデビル"
"The Healing Devil"
November 9, 2002
7
"はじめての仲魔"
"First-Time Demon Partner"
November 16, 2002
The team arrive at a dried-up lake encompassing a treetop village, whose inhabitants rely on the ice demon Issitoq to stave off the heat. A feud then breaks out between the village chief and his son, the latter leaving the village alongside his siblings and Issitoq. As for the group, they learn the Imperial Army built a floodgate that cuts off the village's water, which is managed by Garm. The team successfully fights off Garm with the help of the chief's son and Issitoq, bringing water back to the treetop village.