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, 'Kaiju'—creatures humanity had never encountered before—made their appearance.

Kaiju from the early Gates were manageable enough to be 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 emerged became incomparably more powerful. As if testing humanity's response capabilities, the Kaiju evolved into entities with high intelligence, overwhelming physical prowess, and special supernatural abilities.

Extermination became difficult with conventional weaponry as casualties mounted, and eventually, Gates began to appear simultaneously across the globe—from Europe and Asia to Africa and South America.

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

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

They launched humanity's final plan.

Artificial Ability Injection Project (AAIP)

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

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

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

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 who could stably use their abilities finally began to emerge.

이들은 더 이상 단순한 군인이 아니었다.

They were reborn as living strategic weapons, created for the sole purpose of hunting Kaiju.