On one fateful day, when everyone went on with their mundane lives, the Earth was found in the Dark Forest known as the universe, resulting in unknown extraterrestrial beings preying on the weak — the humanity. Grey, an intern, was then killed due to an alien invasion, only to find himself reincarnated in the mysterious world known as Magica. But wait... "I've become an alien?!" Integrated with a mysterious entity known as the Extraterrestrial System, follow Grey's journey as he begins to seek the mysteries of the world while gradually, slowly, but surely building his Alien Empire despite being surrounded by powerful existences such as Heroes, Demon Lords, and other magically powerful beings.
Every labyrinth in existence could be said to be a part of certain history, whether it was lost or known; the Labyrinth of First Sin was not any different.
In time immemorial, this deep labyrinth containing ten floors that had been buried as the civilization progressed was historically known as the Execution Temple of Emperor Azad.
In some rooms of the labyrinth that had already been explored, Duke Eronheim and his men acquired historical records written in ancient scrolls, and one of the most intriguing things about this temple… was that its depths were, in fact, an execution ground against those who committed treason.
Or… to say the least, those who harbored 'prideful' thoughts, thinking they were mightier than Emperor Azad. That being said, since the temple seemed to have become a burial ground, the monsters from its depths resembled those that died from his absolute word.