Monster Tamer is the Worst Class - Chapter 30: Vibration

Young Jiang Tian has a great aptitude, but because of bloodline problems, he turned into a laughing stock and was suppressed!

At the most frustrating moment in life, fate suddenly reversed!

Relying on the mysterious magic weapon left by his mother, Jiang Tian merged with the blood of the savage dragon to rise strongly and crush all geniuses!

However, as he continued to grow, he found that the people and things around him were not that simple, and even the world was full of huge conspiracies and weird secrets!

- Description from MTL

One day, a Tower appeared, and with it a proclamation by God that Humanity is to be judged for becoming too corrupt.Regression…It’s an ability so fraudulent that it doesn’t require any detailed explanation.Yes, I also agree that it is a fraudulent ability, but…Isn’t it too much to regress due to just a slightest injury…?

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 MC entered the body of the An family eldest son, An Ziran, an arrogant 16 years old boy who weighed 78 kg (~171-172 lbs), who only knew how to eat, play and sleep. Seeing his current body, An Ziran decided his first priority was to LOSE WEIGHT!