Gintama: Planetary Guardian

Three thousand years from now, the nations of Earth plunge into an unprecedented nuclear war. Earth’s civilization and ecosystem are nearly destroyed. The war ends through the nations’ mediation, but the ecosystem is all but completely ruined, and fewer than one in twenty people survive. The survivors resolve to rebuild Earth’s environment, but the effects of the nuclear war give rise to one giant beast after another, each posing a grave threat to humanity. After nuclear weapons defeat the beasts twice, more and more new ones appear. The remaining humans eventually split into two camps with completely different ideas. One proposes building giant robots and using mechanical power to fight the beasts, an approach supported by most people. The other, supported by only a handful, proposes a God-Making Project that draws on the power of the planet itself. But the plan is dismissed as an absurd joke, too impractical to work and doomed after several failed attempts. Then, years later, a mysterious force descends upon Earth, and everything changes.