The Heiress's Return: From Zen to Zenith - Chapter 1595

Zheng Tan somehow returns to the year 2003, turning into a black cat. Picked up from a rubbish heap by the Jiao family, he is given the name “Charcoal”, and so begins the life inside Professor Jiao’s family. Zheng Tan remembers that he was once a person, but currently his body is that of a cat. He has no way of speaking the human language, but can understand it, and even retains the thinking and IQ of a young 20 year old youth. Read along as he adapts to this new world, and somehow tumbles from a group brawl to catching a thief.

- Description from Novelupdates

The mentally disabled 13 year old daughter of the Ye family, one day re-births! She rules over the Omnipotent God’s Cauldron, she possesses a spirit cultivation space. She’s no longer the good-for-nothing, abandoned girl who everyone bullies whenever they see her! With her incomparable poisons, even miracle doctors have to move to the side.

Spirit beasts beg for contracts, but too bad, even the God of Beasts have to call her Boss. Scum father, you dare to abandon your wife and daughter, she will surely make him destitute and homeless. People of the world, you dare to bully her, to insult her, she will definitely pay them back a hundredfold.

Reborn again into the world, she returns as a sovereign, but who knew she would attract the nefarious-blood-thirsty-demon him. He’s definitely the sly emperor who doesn’t hesitate to kill and cut down anyone, but he transforms into a harmless foolishly cute prisoner prince of an enemy country……

- Description from novelupdates

Uchiha Kai has been cautious since he came to this world. He vowed that he must be cautious and go to the end.

But one day he received a mission – to cover the wave wind team to blow up the Kamabashi Bridge, Uchiha Kai knew that he was going to be unlucky…

- Description from novelbuddy

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.