Doomsday: I Have a Mission System

Monsters resembling aliens suddenly invaded Blue Star. They were nearly impervious to bullets, and only rifles and more powerful weapons could inflict any damage. They arrived in overwhelming numbers, dealing Blue Star a devastating blow from the very beginning.

Before the monsters came, the protagonist obtained a mission System. He could exchange mission rewards for all kinds of technology and equipment to strengthen himself.

This novel and its characters are entirely fictional. Any resemblance is purely coincidental. Do not imitate.