Jitsu wa Ore, Saikyou deshita? ~ Tensei Chokugo wa Donzoko Sutāto, Demo Ban'nō Mahō de Gyakuten Jinsei o Jōshō-chū! - Chapter 99: Demon who was Flying and on Fire(?)

Rainer, an amateur arcanist and college student, sought to create a new spell far surpassing the magic of the few he inherited from his grandfather. Yet the interference of an unknown event during the casting of his spell led him to be thrown through space and time.

A man who was once called the world’s strongest agent ended up becoming a teacher after his retirement, to train a new generation of agents. After many years of training his disciples, he was killed at the age of 60 by a secret organization’s ruse and was reincarnated in another world with his memories intact. Though he was surprised by the existence of magic and the strange species in that world, he quickly adapted to his condition as a newborn and took advantage of it. He acquired special magic and gained a massive amount of strength thanks to his rigorous discipline, in order to reach his goal: Resume his career as a teacher which he left halfway through in his previous life. This is the story of a man, who, based on the memories and the experiences of his previous life, became a teacher who travels through the world with his students.

After Wang Mang died, he turned into a giant python, evolving crazily!

With the help of his family, he is getting bigger and bigger!

From the first few meters, tens of meters, to hundreds of meters!

From the Burmese python, to the Titan python, to the deep sea python!

When Wang Mang’s size reached hundreds of meters, the earth’s catastrophe came…

- Description from novelbuddy