My Harem Will Help Me Get My Revenge - Chapter 2: Failure is not an option

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.

The obsessed Big Brother, the loyal God, the yandere Vampire, the cold Honor’s Student…

When a grand variety of Prince Charmings arrive continuously, what should a person feel like? Luo Liyan held her poor aching waist, raised her head to the skies and sighed, give them to whoever wants them!

“What, want to run after seducing me?” That man with strong possessiveness approached little by little, trapping her in a corner. “Little Yan, what type do you like? I can always satisfy you, as long as you stay at my side!”

Looking at that man who seemed more devilish the more he smiled, Luo Liyan trembled as she hugged herself.

Cries… So terrifying. Who the hell forcefully gave and took like this guy?

- Description from Novelupdates

(Based on LN) Tanya von Degurechaff - once a soldier of the Empire fell in the battle unfairly through that being shameless intervention.**Cursed Being X!**The promised destruction of the soul, and so called last reincarnation is a lie by that being. Tanya - or her new given name Tsuyu Uzumaki found herself in the world of Shinobi - with fox-skinned Godzilla named Kyuubi destroying the village on the day she and her twin brother Naruto were born.Tanya once again curse Being X in her heart because she knows this world is far more dangerous than the last. But that does not stop her from her goal of being able to sit on top and leisurely enjoy life. Therefore, she will rise through the ranks, finding opportunity for herself to finally sit at the throne of Hokage! Or the Konoha Council - eyeing the position similar to Danzo, Koharu and Homura.This is her journey!

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