In the past, the world was bundled with demons by the evil dragon Diabolos, and demons were ferocious. However, 14 years ago, Diabolos is defeated by Zard, a boy who was called a hero at the age of seven at the time. He calmed down the demons, and returned the world back to its peaceful state. Four years later, however, Diabolos was resurrected and the demons began to attack the world once again. Zard headed to fight Diabolos again, but he never came back.... On 4996, Kai, Zard's best friend, traveled to see whether what Zard said about humans and demons coexisting together was possible. During the journey, he meets Izayoi, a strange boy who can speak to demons with his heart; and Gend, a brown-skinned swordfighter who seems to be a survivor of the Dark Elves race. Kai discovers that perhaps, they are the key to the coexistence of humans and demons, which led to him traveling together with them.

曾经在这个世界上，怪物被邪恶的迪亚波洛斯捆绑在一起，怪物变得凶猛。,然而，在14年前，当一个7岁的男孩Zard击败Diabolos时，恶魔们平静了下来，一个和平的世界降临了。 ,但是，四年后，迪亚波洛斯复活了，这些怪物又开始变得凶猛起来。,扎德（Zard）打算再次见到Diabolos，但他再也没有回来... ,4996年，扎德（Zard）最好的朋友凯（Kai）前往旅行，看看扎德（Zard）的“人类与魔鬼并存”是否真的可能。,在旅途中，他遇到了一个神秘的男孩“ Jurokuya”，他可以与魔鬼和一个幸存的棕色皮剑客“ Gend”与一个黑暗精灵进行交流。 ,Kai发现其中存在“人类与魔鬼并存”的可能性，并开始与他们同行...曾经在这个世界上，怪物被邪恶的迪亚波洛斯捆绑在一起，怪物变得凶猛。,然而，在14年前，当一个7岁的男孩Zard击败Diabolos时，恶魔们平静了下来，一个和平的世界降临了。 ,但是，四年后，迪亚波洛斯复活了，这些怪物又开始变得凶猛起来。,扎德（Zard）打算再次见到Diabolos，但他再也没有回来... ,4996年，扎德（Zard）最好的朋友凯（Kai）前往旅行，看看扎德（Zard）的“人类与魔鬼并存”是否真的可能。,在旅途中，他遇到了一个神秘的男孩“ Jurokuya”，他可以与魔鬼和一个幸存的棕色皮剑客“ Gend”与一个黑暗精灵进行交流。 ,Kai发现其中存在“人类与魔鬼并存”的可能性，并开始与他们同行...