Reincarnated As The Villainous Extra With SSS-Rank System - Chapter 8:Yunshan Mountain.

Humanity was on the brink of destruction. Muyoung, an assassin from the Forest of Death, fell to his knees. There were corpses all around him. For years, he had worked for the Forest of Death and had finally been able to eradicate them. Now, he, himself, was about to die. He closed his eyes as he felt his heart stop beating.

After a mishap, he accidentally became the protagonist. Unexpectedly, he and the villain cultivated together and they actually became dao companions.

“If you want to be with me forever, there is only the supreme road of achievement. Are you willing to travel with me?”

“Of course I’m willing.”

……

In Li JinZhi’s view, the protagonist and villain’s coexistence should be like swords and spears facing each other, a feud.

But when he crossed into the novel and became the protagonist; when he placed all his trust in the man who was supposed to be the villain; when the other side revealed some unusual feelings to him; when he held Ye Yu’s hand to the altar, he discovered that the relationship between the protagonist and villain isn’t as dull as he imagined.

When the monotonous pattern is broken, the feelings of resentment turns into sharing a common destiny.

- Description from Novelupdates

There are always four kinds of people in the traditional Mary Sue world. The Male Lead, the Mary Sue female lead, the woman who never wanted to see the female protagonist live a good life, and the infatuated man willing to destroy heaven and earth to get the female lead.