In the near future, a portal to [void] has opened somewhere in the world. Monsters are crawling out of the portal and rampaging. Humans have built [villages] around the radius of [void] to keep them safe. Humans also used the monster's gene, the [red eye], to create cyborgs and thwart monster attacks.
And 20 years have passed. The dormant [void] suddenly started to expand again. Our protagonist, Rin, needs to investigate the reasons behind her and save humanity from extinction.
