I'm The Devil - Chapter 143: "The Extermination Of The Song Clan"

A man is reborn into the world of Avatar: The Last Air Bender as a waterbender from Katara's tribe. Best of all, he was the same age as her, and he had a system with him to help.He knows the future and a system that lets him continuously get stronger by completing quests or long-term missions, as well as giving him the ability to copy abilities from others for himself. He will become invincible in the world of Avatar, even more so than the Avatar himself.

Ye Xiwen was previously only an ordinary university student on Earth, but unexpectedly crossed through into the world known as the Zhen Wu Jie world! In this world, formidable warriors are capable of turning over mountains and collapsing the ocean, destroying the sky and extinguishing the earth! He originally had ordinary aptitude, because of that he received the mysterious special space! Any martial art can be deduced within the mysterious space, other people practice for decades, he only needs a year! So long as he has enough spirit stones, any talents he faces are all floating clouds!

- Description from Novelupdates

France, 1934. The scars of the Great War still shape the military minds of the Third Republic. Trapped in the past, its generals place their faith in fortifications and defensive warfare, while across the Rhine, a new German army rises, faster, deadlier, and ready to crush everything in its path.Into this world awakens Captain Étienne Moreau, a man who should not exist. He remembers another life, one where France falls in 1940, where German tanks storm through the Ardennes, bypassing the Maginot Line. One where his country surrenders in a matter of weeks.But here, now, he has a chance to stop it.As an officer in the 2nd Armored Division, he fights for reforms: pushing for mobile tank warfare, warning of Hitler’s growing ambitions, and challenging the high command’s obsession with World War I tactics. Yet, his ideas are dismissed as radical, madness from a young officer who “thinks he knows war.”Surrounded by political intrigue, military infighting, and rising fascism, Moreau must carefully navigate the system, winning allies among future leaders like Charles de Gaulle, while avoiding suspicion from the French High Command. His knowledge is a double-edged sword, if he is too aggressive, he risks being labeled a traitor. If he does nothing, he will live to see France burn.As war draws closer, Moreau faces a terrifying question: Can history be changed? Or is France doomed to fall, no matter what he does?Time is running out. The Blitzkrieg is coming. And he may be France’s last chance to fight back.