Monster Calamity 2124

[Genderbender + Sequence-Based Powers + Overpowered Heroine + Short Story (A Sequel Is Planned)]

In 2124, after a certain country that was doing rather well for itself, R Country, spent a century discharging nuclear wastewater, Earth's ecology underwent drastic changes. On July 1, 2124, the first monster disaster finally erupted. Later generations would call this day Monster Disaster Day.

The first monster disaster lasted six months. R Country was wiped out completely, and the monsters responsible for the catastrophe all vanished beneath the horizon.

After Monster Disaster Day, the major powers put emergency plans into action. China's New Star Project, America's Special Warrior Project, Russia's Mecha Project, and others were launched one after another.

Countries also began building fortified cities, constructing large-scale defenses and underground cities, preparing for disasters that might come in the future...