I Am Really Not the Demon Lord!

Story:

A brief description of the manhua I Am Really Not the Demon Lord! Awakened from killing, to become the strongest demon lord! To survive, Fang Cheng is forced to sign a contract with the “Killing Devil”, and unlock skills by killing other devils, in this dark age under the invasion of devils, Fang Cheng swore to become the strongest, and kill his way towards being the strongest!