Hakai Me no Yuuri - Chapter 12: Let’s Get Ready to Head Out

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.

Zhou Yu is just an ordinary person. After his heart attack, he was born again. He thought he could enjoy life well, but he didn’t realize that this world was a supernatural world. He always bumps into ghosts and a group of samsaras would use him as a NPC. His lover always turns into a horror movie BOSS.

- Description from Novelupdates

Transmigrated to become a disciple of the demon sect, relying on the technique modifier to become a giant of the demon path.

[Detected the technique “Blood Nerve”, relying on devouring blood to cultivate]

[Side effect: easily affected by the spirit contained in the blood, becoming bloodthirsty, murderous, insane, and even brain dead]

[Please wait, system modification is in progress…]

[Ding! Modification completed and side effects canceled]

“Teacher, you know me. I’m usually a good student, with nearly 100% attendance, and I’m also eager to help the people.

Yesterday I flew to the coast to fight monsters, so…”

“Teacher, you know me. Which teacher is not full of praise for me, but things are prioritized. Yesterday happened to be the Ghost Festival. Hundreds of ghosts walk at night, so I…”

“Teacher, you know me well. I am an activist in our dormitory. Every day I call them to go to class, but under special circumstances, so…”

“Teacher, I’m a foreigner, I don’t understand what Xie said, and I didn’t know there was a class yesterday, so…”

The teacher took off his glasses and rubbed his temples, “I can tell that everyone in your dormitory has stunts, but this is by no means a reason to skip class! This class! This year! You guys are all done!”

————————

Another version of the introduction: Ultraman Delta was living in another world for unknown reasons. Originally, he wanted to be an ordinary college student, waiting for one day to find a way to return home.

But the sudden appearance of a monster disrupted his plans, and he also discovered that his roommates were not ordinary people either.

- Description from novelbuddy