As a baby Jiro was delivered to his foster parents by a massive oni, who said he would return for Jiro in 15 years. When the time comes Jiro must contend with enemy oni, dark cultists, and their minions while attempting to protect both his parents and girlfriend from their depredations. Ultimately he must embark on a journey through the past, future, and other dimensions to embrace his destiny as Shuten Doji reborn.

Looking at Miyuki and Tatsuya now, it might be hard to imagine them as anything other than loving siblings. But it wasn't always this way.. Three years ago, Miyuki was always uncomfortable around her older brother. The rest of their family treated him no better than a lowly servant, even though he was the perfect Guardian, watching over Miyuki while she lived a normal middle school life. But what really bothered her was that he never showed any emotions or thoughts of his own. However, when danger comes calling during a fateful trip to Okinawa, their relationship as brother and sister will change forever…

As New Year’s Eve draws closer, preparations for a holiday party are underway in Petersburg. In anticipation of the event, Eila Ilmatar Juutilainen of the 501st Joint Fighter Wing is determined to take Sanya V. Litvyak on a leisurely walk around the city. However, despite Eila's best intentions, she gets interrupted every time she gets a chance to ask Sanya out, ruining the moment and separating the girls. To make things worse, a Neuroi is approaching the base, threatening both the squadmates and the celebration in Petersburg.

On August 10 2002, the eruption of Mount Fuji, as well as a series of large-scale earthquakes tsunamis inflict tremendous damage to Japan, sending the country into a state of emergency. Furthermore, another massive earthquake hit Japan on August 15, splitting the country into two. While Japanese refugees were taken in by various countries, the Japanese government accepted aid from China and the United States, which eventually caused China to govern the North, and the USA to govern the South. 15 years later, the Japanese refugees residing in Taiwan and the Taiwanese citizens find themselves clashing with one another, due to job competition and the unimproving conditions of the Japanese refugees. Genichiro Ryu is a survivor of the catastrophic events that took place in Japan, but was raised in Taiwan by a couple who adopted him. He gets himself involved in the situation between the Taiwanese and the Japanese, hoping that the two parties will be able to coexist with one another.