I Lost the Leash of the Yandere Male Lead - Chapter 4

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.

Luo Wencheng made a deal with a certain existence and went back in time to ten years ago, when he had just been released from prison, still young and healthy, not yet pushed to the breaking point by Luo Wenjun and not yet used by him as a prop to test drugs for profit until his tragic death.

This time he was going to trample Luo Wenjun underfoot.

The first priority was to steal Luo Wenjun’s future backer from him.

- Description from Novelupdates

Kurokawa Risa is an ordinary office worker, who has practiced lots of cooking while living alone. One day, she wakes up in another world, with a concerned little spirit hovering over her! She has apparently been transported to a magical, spirit-filled realm by the will of the goddess, and there is no known way for her to go back. She is taken in by a wealthy couple, and they and her new spirit helper treat her with nothing but kindness. There is one problem, however–the food in this magical world is gross! Risa insists on helping the household cooking staff prepare a traditional meal from her world, and it is a big hit with her hosts. Soon Risa knows what she should do in this new world; she should open a cafe and treat everyone to delicious food!

In a world where dungeons were an essential part of it, Rein was trying to conquer as many as possible. They were the key to gain powers in the fastest possible way. So, to reach his full potential and to become the strongest, he became a great dungeon conqueror.With his trusty friends and lovers, he was definitely going to reach the peak alongside everyone. Join Rein and see how he went from strong to stronger and then the strongest.__________________1. The harem would not be too large(I'm not sure how many but probably just 4-5 main and few other here and there). All the girls would be getting their time and story.2. The story is starting when the MC is in the middle of his growth stage and not at the very beginning. But his beginning will be mentioned in the story in some form.3. I don't think I need to mention this, but obviously it will not have any NTR, rape or that kind of stuff. It is actually quite a wholesome story focusing mainly on adventure, action and bit of romance and slice of life.