Even in Another World, We Must Start from the Demon King

A secret mission, a killer. After breaking through the layers of siege, he finally killed the target. And then, a gunshot rang out. When the task is completed, it is also the moment of death. The strongest killer was reincarnated into a different world. After a difficult battle, the reincarnated Chen Cuo died again. But he also gained the approval of the Demon King and was resurrected again. This time, it was no longer a cowardly knight, but the invincible Demon King. This book is an invincible dragon Aotianliu, with a mechanism, the male protagonist is not a virgin, not full of sympathy, and has a certain amount of reasoning ability.