"If you want to kill me, you're going to have to learn from me." The Demon King needs to die. He must be slain or else he will bring an end to the world. Armies have tried. Monsters have tried. All have failed. Until he finally offers the world one last chance with one single request, "Let me make my own murderers." Five young adventurers find themselves entangled within the fate of the world when they are given the impossible quest of killing the Demon King. Their only advantage, the Demon King is going to teach them how. Will they suffer the same fate as others, or will the demon's unorthodox tutelage be just what they need to succeed? They have five years to give the impossible a go. Their time starts... now.