Mo Qing / Li Chen Lan

Son of the Demon King who had originally planned to kill him after transferring his own heart demon into him. Unable to do so, he seals his power and traps him in Mount Feng while searching for a way to rid him of the demon. The seal creates visible blue scars on his face and body.

Kindhearted but powerless, in a world that highly respects power, he is captured and put on trial for the crime of his existence. He is rescued by Lu Zhao Yao and falls deeply in love with her.

After gaining the Wan Ju sword, the seal his father placed on him is broken, his blue scars disappear and he is able to develop his power unrestricted. Guilty over causing the possible death of Lu Zhao Yao, he takes control of Wan Lu Sect, even while still searching for her.

(Source: Lady_Dragon at MyDramaList)