Mentioned Characters: Reimu, Cirno, Eternity

"Hey, Cirno. See the door on my back? Lemme teach you how to use it. I bet you'd pick it up quick. ...Hm? You're scared? Now that you mention it, I guess it is kinda creepy." During the bizarre incident later known as the Four Seasons Incident, all four seasons appeared at once. Most people figured Reimu or someone would sort it out before long, so they treated it like a festival and enjoyed the chaos. Nobody realized just how wrong things were until much, much later.

Prolonged Incidents Maybe some incidents drag on because the masterminds behind them are too powerful. People tend to think incidents just happen on their own and eventually resolve themselves. But in truth, an incident that's resolved too easily has no meaning, while those that can't be resolved can have disastrous implications. Incidents are necessary to keep Gensokyo on track. At their core, they are symbols of change, and both humans and youkai live within that constant flux. Every incident has to be orchestrated according to some intricate plan. Otherwise, it would all fall apart.

The Prolonged Four Seasons Incident All four seasons appeared in Gensokyo at once. Some claimed strange doors had appeared on everyone's backs. Others spoke of suspicious objects flying through the sky. It seemed each region had become locked into a single season. Hakurei Shrine was stuck in spring, the Garden of the Sun in summer, the Youkai Mountain in autumn, and the Forest of Magic in winter. Each season was beautiful in its own way, but seeing them all at once was sheer insanity. If the incident were allowed to continue, the warm air rising from the Garden of the Sun would collide with the freezing air from the Forest of Magic, creating abnormal wind currents. That might not sound dangerous, but wind currents shape a region's climate. Gensokyo's temperament would fall out of balance, until one day, all that remained would be a single gray season with no end.

EX Beings The "EX Factor" is believed to cause prolonged incidents and is said to be found in worlds with EX Beings. It can be thought of as a special kind of temperament. "EX" is generally understood to stand for "Extended." Something extended inevitably contains unnecessary elements. In the case of prolonged incidents, those elements can be labeled as "false data."

Eternity Larva is a swallowtail butterfly fairy. The god of the new world whom she speaks of, and the God of Eternal Night, said to be associated with her, remain a mystery. No individual by the name of Ooube no Oo has appeared in the true data yet. That name does appear in the outside world data, but precious little is known about who or what they truly were. The false data, however, tells a different story. Supposedly, Ooube no Oo was one of the many evil gods destroyed long ago by Hata no Kawakatsu―a human once known as Uzumasa, who was revered for their godlike powers. Some accounts even claim that Hata no Kawakatsu exterminated the violent gods whose spirits troubled Prince Shoutoku's ears, then seized their divinity and made it their own.