MTL - Marshal, She Has Seven Appearances a Week - Chapter 8 I let you off last night,

The one single goal in life of the Strongest Old Sage is to subjugate the Demon King. In an epic final battle, both of them met their mutual destruction at each other’s hands.

However, the Demon King was not completely destroyed!

In order to destroy the Demon King once and for all; post-death, the Old Sage trains in the World of Gods and reincarnates as the Apostle of the Gods, Will.

In the reincarnated future, the Old Sage had become a legend and his former disciples hold the supreme authority in the world. The disciples had created an organization to oppose the Demon King and an academy to nurture the new generation of Heroes.

Thus the Apostle of the Gods, Will (8 year old), enrols into that Academy of Heroes.

This is the story of a boy on a mission to save the world through epic battles while enjoying Academy life.

Eight hundred years ago, Xie Lian was the Crown Prince of the Xian Le kingdom. He was beloved by his citizens and was considered the darling of the world. He ascended to the Heavens at a young age; however, due to unfortunate circumstances, was quickly banished back to the mortal realm. Years later, he ascends again–only to be banished again a few minutes after his ascension.

Now, eight hundred years later, Xie Lian ascends to the Heavens for the third time as the laughing stock among all three realms. On his first task as a god thrice ascended, he meets a mysterious demon who rules the ghosts and terrifies the Heavens, yet, unbeknownst to Xie Lian, this demon king has been paying attention to him for a very, very long time.

- Description from Novelupdates

Rebirth in 2009, but this rebirth posture seems a bit wrong.

In this life, the family is wealthy, Wang Ye is addicted to the Internet, and can stay up all night the day before the college entrance examination.

Helpless, Father Wang decided to send Wang Ye to serve as a soldier in the army to quit Internet addiction.

two years later…

When Dad Wang made a video call with his son and was about to ask him when he would be discharged from the army and come back to inherit the family business.

Wang Ye, who was dressed in the uniform of an officer, directly surprised Father Wang.

“Dad, I’m going to be a general in the army all the time, so what, in terms of family business, why don’t you and mom consider having another one?”

……

- Description from novelbuddy

Emperor Gabela: Imperial legions are unstoppable on land.

Great Orc Chief: All the warriors of the tribe can count as ten.

Jade Realm Elf King: The forest ranger has never missed a shot.

Chairman of the Horn Bay Alliance: The alliance fleet is the undisputed ruler of the sea.

A mysterious organization: The prophesied era will finally come.

Paul Grayman: I am not targeting anyone. Everyone here is rubbish.

Start the journey of guns and cannons crushing the low-magic plane…

(This is an old-fashioned story about climbing a technological tree in another world to farm for hegemony. The author has limited knowledge and may make some mistakes in technical details. Criticism and corrections are welcome)

- Description from novelbuddy