Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 16 - 16-50. Vampires

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

Within the popular VRMMORPG «New Genesis», there was a ranker by the name of Arthur Holmes, commonly known by his in-game alias «Merlin».

When I read the development of the heroine getting stolen away, I left a malicious comment to the author.

But then I woke up later, and I’m now the villain who is supposed to steal the heroine.

He had crossed into the dark, ruthless Wizard World.Lucien found his system somewhat different from the usual golden finger.System upgrade points? Chip activation?None of these, but rather becoming a role model, transforming into a nurturing breeze:Teaching students knowledge, receiving advanced knowledge in return.Caring for and maintaining students, earning generous rewards.[Your student has mastered the Magic Potion “Kuru's Cough,” congratulations on acquiring the improved formula “Kuru's Cough - Enhanced”!][Your student has mastered witchcraft “Fireball,” congratulations on learning witchcraft “Greater Fireball”!][Your student has successfully crafted the wizard's tool “Pale Mask,” congratulations on acquiring the wizard tool’s manual “Revised Pale Mask”!]Initially, Lucien was resistant.But after experiencing what it was like to teach disciples and outdo them, Lucien felt he had completely transformed into the form of the master system.This thing, isn't it much more useful than something called Cheating Device?