It all began with the first 'Gate' that appeared in the United States.

An unidentified dimensional rift emerged in the middle of a city, and from within it, creatures humanity had never encountered before—'Kaiju'—revealed themselves.

Kaiju from the early Gates were manageable enough to be suppressed with modern firearms and armored forces alone. Nations worldwide perceived this as a new form of biological disaster and mobilized their militaries to control the situation relatively easily.

However, that was only the beginning.

As time passed, the Gates grew larger, and the Kaiju emerging from them became incomparably more powerful. As if testing human response capabilities, the Kaiju evolved into entities with high intelligence, overwhelming physical prowess, and special supernatural abilities.

Conventional weaponry only led to increasing casualties while failing to subjugate them. Eventually, Gates began appearing simultaneously across the globe—beyond America to Europe, Asia, Africa, and South America.

Human civilization faced the greatest crisis of extinction in its history.

In this desperate situation, major world powers set aside political conflicts and established a joint research institution.

Their final plan for humanity:

Artificial Ability Injection Project (AAIP)

This project aimed to artificially awaken supernatural powers in the human body using unknown energy extracted from Kaiju corpses and special substances found inside the Gates.

Most experimental subjects were special forces personnel and soldiers from various nations.

However, humans were not originally designed to accept such power. Numerous subjects lost their lives to physical collapse, mental contamination, and berserk phenomena, resulting in an extremely low success rate.

Nevertheless, humanity had no luxury to mourn the failures.

Project leaders defined the sacrifices as an 'inevitable cost for human survival,' and after countless losses, superhumans capable of stably using their abilities finally began to emerge.

They were no longer mere soldiers.

They were reborn as living strategic weapons created to hunt Kaiju.