I Am the Grim Reaper in the Mirror World

The portal that suddenly appeared in the world turned out to be a mirror? Due to the emergence of portals in the world, various countries began to slowly enter the portals to investigate. Those who entered the investigation discovered a crystal, and this crystal allowed people to evolve, and people with superpowers began to appear in the world. In this mirror world, terrifying alien beasts appeared, and humans began to fight against the alien beasts. The world era was also changed to a natural disaster by the heads of countries. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.