When his friend gifted Leonardo McDougall an ancient grimoire, the psychology major just laughed it off. To prove that the thing was fake, he even set up a ritual to summon a demon... Strangely enough, when demons had summoned him instead, he didn't find it funny at all.  The Demon World doesn't greet him with open arms or a warm welcome. Weak and alone, Leo needs to use his wits and unique Class just to survive and keep his freedom. Here, humans are near extinct, and the few survivors are treated as exotic pets. Here, the only thing you can rely on is your strength. Those with a powerful Race, a rare Class, and a high Level decide the rules and the rest can only obey.  With the forbidden [Demonologist] Class, which's the bane of this world's rulers, Leo shall climb to the top. Watch the beginning of his legend as he turns from prey to hunter, from slave to master, from human to God.