DxD: Building A Demon Clan From Scratch. - Chapter 31: Team Match

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.

Jiulong Continent, ancient times had Nine Dragons!It is said that one who obtains a dragon can stand above billions of people; one who obtains nine dragons shall become the ruler of the continent!Young Yun Xiao, in an attempt to save a treacherous individual, suffers severe injuries to his meridians. However, he experiences an extraordinary twist of fate and rises from dire circumstances. He merges with the soul of the Dragon Sky War God and is reborn, thus beginning his own legendary tale of defying destiny.“Eh? Isn't this a parasitic wasp?”“Who says it is a parasitic wasp? Have you ever seen a golden parasitic wasp?”“Even if it is golden, it's still a parasitic wasp!”“No, it is a dragon!!!”

Liu Fang, a manager, died suddenly at work due to being too diligent.
She thought that she would turn into a wisp of dust and dissipate after her death, but she never imagined that – the new century, the new underworld, even if she became a soul, she would still be a worker!

Liu Fang has become a newcomer to the underworld Quick transmigration Department. In order to wait for a good reincarnation, she strived to accumulate merit and traveled into one world after another to repair the way of heaven.

- Description from Novelupdates

A thousand years ago, the world shattered.Mana surged into existence, rewriting reality itself. Dungeons tore through the land, birthing monstrous horrors, while beasts mutated under the influence of Primordial Ki, evolving into unstoppable apex predators. Humanity was on the brink of annihilation—until the Awakened emerged, wielding supernatural power to defy extinction.Yet, in this brutal new world, strength reigns supreme, and weakness is a death sentence.Amidst it all, Azvoid Larkson—a nameless figure among the countless struggling to survive—awakens a power beyond reason. A power tied to ancient, forgotten dragons—beasts feared even by the strongest Awakened.With each battle, he ascends. With every dragon he tames, his legend grows.In a world where only the strong thrive, how far can one man rise?