I'm an Infinite Regressor, But I've Got Stories to Tell - Chapter 148

What happens when a scientist from a futuristic world reincarnates in a World of Magic and Knights? An awesome MC is what happens! A scientist’s goal is to explore the secrets of the universe, and this is exactly what Leylin sets out to do when he is reincarnated. Dark, cold and calculating, he makes use of all his resources as he sets off on his adventures to meet his goal. Face? Who needs that… Hmmm… that guy seems too powerful for me to take on now… I better keep a low profile for now. You want me to help you? Sure… but what benefit can I get out of it? Nothing? Bye. Hmmm… that guy looks like he might cause me problems in the future. Should I let him off for now and let him grow into someone that can threaten me….. Nahhh. *kill*-

Alternative: Leylin is transported from an advanced technological era into a medieval world— except there’s magic. Equipped with “only” his quick wits and an A.I. chip fused to his soul, he sets out to become the most powerful magus the world has ever known. In a land divided into the Light and Dark Magi, the weak can either be cattle or disposable slaves. Only the strong can determine their lives, and only they have the luxury for virtue. Yet strength is only a tool for Leylin, like any other. His goal, in the end, is his own.

I was betrayed in my first life.A cripple, broken and discarded—I died after catching the one I loved in bed with the only person I ever called a friend.That was the start of real torment.When I woke up, it was in another world.A goddess stood before me.She told me I could go back.Back to my world.Back to everything I lost.All I had to do… was play my part.The side character.And I did.I followed the script.Played my role to perfection.They hated me.Mocked me.Used me.Again and again.But I kept going. Because I believed her.Because I wanted to go home.Then one day, I found out.The hard way.It was all a lie.There was no going back.There never was.She used me.Again.Just like everyone else.Thrown away like trash once I outlived my usefulness.That was the day something inside me snapped.And so, I made a vow.I would take everything from her.I would enslave every single heroine she chose.And I would kill the hero she placed all her hopes on.If she wanted to protect this world…Then I would burn it down.But the more I tried, the more things started to change.And then one day—I found one of the heroines.One of the hero's yanderes I had enslaved.She stood there, trembling, a knife in her hand.“You’re not going anywhere,” she whispered, eyes wild.“I won’t let them have you. You belong to me.”...What. The. Fuck. Is. Happening?!

The well-known and recognized throughout the Stern continent, strong and mighty, as well as the unique Wizard of magic cures, the most outstanding genius of the whole continent, Jason got into the flow of time, back in the uncivilized era during the first failed experiment, 3000 years ago. This was the period when the magic healers didn’t exist. How will Jason apply his knowledge in this backward era, wherever he reach the peak of glory?

- Description from Novelupdates

When a boy in a medieval fantasy world wakes up with the memories of his past life, he discovers a secret buried deep within his mind—a highly advanced AI companion. This AI, a relic of his previous existence, holds the knowledge of a futuristic world filled with technology, science, and innovation.Armed with this unprecedented advantage, the boy embarks on an extraordinary journey to transform his medieval surroundings into a thriving futuristic utopia. From reinventing agriculture to creating advanced cities, he introduces ideas far beyond the comprehension of his peers. But his vision isn't without challenges—power-hungry nobles, skeptical commoners, and ancient magical forces stand in his way.