Demon Contract? No, It's a Demon Hunter System

Retired special forces soldier Rain, scarred by the horrors of war, retreats to a cemetery to live in seclusion. But one rainy night, he encounters a rubbery monster digging up graves and devouring corpses. His shotgun breaks, and as he lies on the brink of death, a mechanical voice suddenly rings in his mind: [Demon Hunter System activated]! The sharp-toothed monster is only the beginning. What other supernatural terrors are hiding in this remote town? From battlefield nightmares to hunting demons, watch as the System helps him tear the darkness apart!