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, creatures humanity had never encountered before—'Kaiju'—revealed themselves.

Kaiju appearing from the early Gates were at a level that could be sufficiently suppressed with modern firearms and armored forces. Nations around the world perceived this as a new form of biological disaster and controlled the situation relatively easily by mobilizing their militaries.

However, that was only the beginning.

As time passed, the Gates grew larger, and the appearing Kaiju became incomparably more powerful than before. As if testing humanity's response capabilities, the Kaiju evolved into entities with high intelligence, overwhelming physical abilities, and special supernatural powers.

Conventional weaponry resulted only in increasing casualties with little success in suppression, and eventually, Gates began to appear simultaneously across the globe—beyond America to Europe, Asia, Africa, and South America.

Human civilization faced the greatest crisis of extinction in 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 discovered inside the Gates.

Most test subjects were special forces members and soldiers from various countries.

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

Nevertheless, humanity had no room 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 be born.

They were no longer mere soldiers.

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