Interrealm Mobius

In this world, people who fall into despair and cannot extricate themselves have a chance of slowly becoming restless, voluntarily or forced to sign contracts with various dark things, and half of their souls will forever enter the interrealm and become half undead, harvesting human souls in nightmares to maintain their status and soul existence value in the interrealm. Before he met her, who had been harvesting the souls of restless people alone, he never thought that his destiny would be connected to these things when he was studying in an ordinary high school...