Kyoukai senjou no horizon

The beginning of Kyoukai Senjou no Horizon.

There was a point in human advancement were humanity ascended to the heavens like gods. They basically reached a level of development so advanced that let them to manipulate the laws of the universe and expand through all space. But this Age of the Gods ended when there was a War of the Gods and most of the universe, heaven, hell and even fate were destroyed, so humanity had to go back to their homeworld in planet Earth.

When they abandoned Earth, they left behind environmental gods linked to the ley lines to restore the environment and control it so the planet would be in a perfect state for human life to be possible just in case they came back. The problem is that for unknown reasons, the environmental gods went berserk and over-restored the world, making the whole world extreme and uninhabitable with the sole exception being the Divine States, the japanese archipelago (under where the environmental gods were based and controlled the ley lines).

After they descended, there was a ugly war between the descendants of the original dwellers of the Divine States and the rest, a war where due to the spells used, human population was reduced by half in two weeks. Given the extreme situation, they were forced to accept that they would gain nothing going down that path and a Party of Seven Hundred Travelers was assembled to reach the place where the environmental gods resided 6000 kilometers under the surface. Only 31 members survived, but they succeeded.

Later, they agreed in a Plan to Combat Decline and Advance Tuning, that led to the creation of the Testament (a history book from the Former Earth) and the harmonic world (by using the environmental gods), and they decided on the rules for the history recreation. This method would ensure humanity survival, as they linked the Testament with fate itself and gave them enough time to recover their lost tech.

Next time, the Testament Era.

That was the start of the Testament Era, where humanity followed the Testament, a history book that covers each and every aspect of the Former Earth Age’s history. The Testament was composed by Seven Compositions (with an Old Testament that recorded history Before Christ and New Testaments with the history of Anno Domini) and a Excerpt (which only information about the Divine State history). As some people wanted to use the coming history in their own benefit, a spell was attached to the Testament so it would only show the events coming in the next century and renew itself each 100 years.

The Old Testament was recreated pretty fast and with the majority of wars agreed upon, with the proper history recreation in real time starting in the 0 AD. The Divine States history was recreated in the Divine States, while the rest of the world history was recreated in the Harmonic Divine States, an artificial copy of the Divine States with the characteristics of the whole world.

All was going well until the Nanboku-chō period, where one of the rival courts stole the Three Sacred Treasures that maintained the Harmonic Divine States and they collapsed into the real world. That produced a new war between the Divine States and the other countries, the Harmonic Unification War, and after 60 years the Divine States lost. As the Testament never said anything about such a thing, the other countries used the growing influence of the universities and schools in the period to create a system that let them to control the Divine States in a way that didn't clashed too much with the Testament descriptions. So, academies became the highest political and military cores in the Divine States, starting a provisional rule under the pretense of "peace and stability granted through knowledge." After that, the Divine States were renamed to the Far East, and a period of 150 years of provisional rule began.

The actual situation in the world.

Academies became organizations were one would be affiliated to one of them until retirement through graduation, and students ruled the whole politics. Student Council Presidents and Chancellors became the new equivalents to kings and daimyos. All the world countries adopted a different clan in the Far East's side of history and they proceeded to recreate both the world's Early Modern Period and the Far Eastern's Sengoku Era. Also, the Testament Union was formed to ensure the correct flow of history recreation.

The proper Far East was reduced to some settlements around the states, the neutral territory of Mikawa, the capital in Kyou and the Aerial City Ship Musashi flying between the borders of the other countries. The Far East also had their right to own weapons limited and a restriction that forced their students to graduate at 18 years old, so their goverment would be composed by teens, unlike the other countries.

But in 1548, the Testament ceased its update. Strange phenomena began across the whole land, and a rumor that the Apocalypse is coming began to be murmured. 100 years later, the present of 1648, the end of the Testament Descriptions comes more closely, with the very last recorded event being the Peace of Westphalia.

During all of this, the last decade P.A. Oda half-seceded from the Testament Union after the Oda Nobunaga name was inherited and they seem to be in a quest to conquer the world. While the whole world status quo is in jeopardy due to Oda and the Apocalypse, Musashi makes a stop at Mikawa and a plan is set in motion to avert this Apocalypse once the Mikawa Incident unfolds. The centerpieces in this plan are the chancellor and student council president of the Musashi Ariadust Academy, Toori Aoi, and P-01s, the mysterious automated doll he's planning to confess to.

That would be the start of a journey that intends to reach beyond the horizon, attain world conquest and averting the end of days itself.