DxD: Matsuda? - Chapter 31: Training Montage?

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

Reincarnation in a game as the Main Antagonist.It could be a novel itself, but that was what I dragged myself into. In the famous and successful game [Princess And Dragon]As if my life wasn't shitty enough, a bastard brought me in that hardcore violent Dating Sim Game and in the body of the worst villain and [Major Antagonist Edward Falkrona]If I want to survive, I have to become strong.If I want to be strong, I have to join the Academy and by joining the Academy, I will meet these guys...Yeah, I'm obviously speaking about the Protagonist, the Main Heroines, the Villainess and all the villains.Am I destined to watch that protagonist build his harem in front of me?!

Waking up from a deep sleep, Lin Yue found herself having transmigrated into a peasant's new wife, and to make matters more complicated, she was a replacement for a deceased wife. The husband, over a decade older than her, had already lost two former wives. It wasn't so much a marriage; she had been sold to the family by her unscrupulous parents. Her fate was out of her hands. Before her stood one, two, three, four children, like a line of burdens, all gazing at her with blurry and hopeful eyes. Lin Yue felt an enormous pressure, “Thanks to Yuewen Book Review Group for providing review support!”

Mr. Gu, I have a crush on you######Recommending a new book: “Empire Master, You Are Mine”(The main text is completed, feel free to dive in) “Mr. Gu, I indeed have a crush on you. I'm not very brave, and I dare to say such words of liking you only once. If you have not the slightest bit of that kind of feeling towards me, then I will resign right now.”“Very well, An Junxi, no one has ever dared to threaten me.”“...So, what now?”“You have provoked someone you shouldn't have. Stay where you are, I will come over immediately!”