Vincent Strider was a gun for hire who made a living by killing whoever it was his clients wanted dead. But during one mission, he died in a fierce gunfight. However, death was not the end for him. Vincent found himself reincarnated in another world, facing a floating interface that flickered before his eyes. [Synchronizing Host!] [Military System initializing.] Vincent found out that in this system he received, he can summon soldiers, tanks, aircrafts, and even warships! This is going to be exhilarating.
An unremarkable man, who leads a mediocre life until he discovers that he's the long sought after serial killer. Owing to the secret existence that dwelled within himself, he ends up with two bullets lodged into his skull. Just when he was glad his pathetic life was over; [Greetings and welcome to your afterlife, the incinerator, unclean soul. In your previous life, you carried out several atrocities...] Against his weak protests he is plunged into an unknown world as a forsaken son of a god with the goal of atonement and purification of his soul.
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.