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

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

The Kaiju emerging from the initial 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 Kaiju that appeared became incomparably more powerful than before. As if testing human response capabilities, the Kaiju evolved into entities with high intelligence, overwhelming physical abilities, and special supernatural powers.

Subjugation became difficult as conventional weapons only increased the casualties, and eventually, Gates began to occur simultaneously across the globe, reaching Europe, Asia, Africa, and South America beyond the United States.

Human civilization faced the greatest crisis of extinction in history.

In this desperate situation, the world's major nations set aside their political conflicts and established a joint research institution.

Their final plan for humanity.

Artificial Ability Injection Project (AAIP)

It was a project to artificially awaken supernatural powers in the human body using unknown energy extracted from Kaiju bodies and special substances discovered inside the Gates.

The experimental subjects were mostly special forces members and soldiers from various countries.

However, humans were not originally designed to accept such power. Numerous subjects lost their lives due 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 sacrifices, superhumans capable of using their abilities stably finally began to be born.

They were no longer mere soldiers.

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