Hoshi Carmen Takada-Santos, better known as Hoshi Santos, might seem to be an ordinary biracial high school student living in Nara City, Japan, but his other self, the serious, strong, and cold Kuro, is a strong warrior who wields a scythe as his weapon. It’s been 4 years since his father, a Filipino shaman named Louis Santos, had died after banishing an evil entity, only known as Master Black Blood, into the underworld for his atrocities, Hoshi had to hide and conceal Kuro from anyone for his safety. But, Master Black Blood’s son, Master Demon Blood, would do anything to avenge for his father’s banishment from the overworld, and this also means killing Hoshi. This demonic entity also employs the help of Sha Sakiyama, a mercenary and expert on the use of shadow, to get rid of Hoshi. But, Hoshi isn’t alone in fighting the evil forces. His classmate, a reclusive and introverted ninja named Bokuto Sakata, decided to help him out because his father was a close acquaintance of Louis, and a girl named Saki Mizoguchi, who was secretly a mage and had a long family lineage of the use of magic. Dive into the world of both magic and modernity as their quest against the evil supernatural forces begins to unravel.