In a world overrun with vampires, humans have been hunted to the brink of extinction. The only way they can fight back is with a series of demonic weapons known as Cursed Gear. Reserved for soldiers with exceptional talent, these weapons require humans to form pacts with ancient demons in exchange for their power. Yuichiro Hyakuya is a young member of the Moon Demon Company, a prestigious army squadron armed with Cursed Gear and tasked with exterminating vampires. After the blood-sucking monsters killed his family when he was a child, Yuichiro vowed he wouldn't stop fighting until every last one was dead. But when a familiar face from his past appears sporting a new set of fangs, the line drawn between good and evil begins to blur. There's something special about Yuichiro--a dark power that the vampires call the Seraph of the End. When that power is unleashed, will he be the key to humanity's salvation or its complete destruction?