The Guide is Actually a Body-Switching Esper [BL] - Chapter 302: ...Oops.

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.

Reborn in a parallel world, this place is imbued with eeriness everywhere... Do not enter the bathroom after midnight. At two in the morning, the sound of knocking resonates on time. A woman, haggard and emaciated, always stands with her back to oneself. Encountered a strange event? Lucky for me, I can Rewind! This is the story of a Reincarnator, carefully navigating a reality invaded by the bizarre, combating the strange with bizarre poses.

When Bai Xun was bored, she played a dating game recommended by a friend. She entered the game and must keep up the affection with seven different types of men as the only way to clear the game. Only when she gets seven hearts safely can she go home? After many deaths, Bai Xun knew it, and could only live by paying closer attention!!

- Description from Novelupdates

Enemy of the world, cursed by all, Kim Sungchul goes on a quest to prevent the ‘prophecy of the end’ from coming to pass.

But no matter how much he raised his strength, there were still some things he could not achieve with physical strength alone.

Resolving to obtain the power of magic, he goes into hiding to learn magic from his most hated of enemies, The Mages.