My Angel system - Chapter 369 Nova VS The Demon Boss

Oscar, a destitute young boy, died in a tragic accident and was reborn in the forgotten realm. As a member of the lowly Birch tribe, his solace comes from the fragments of a guardian's spirit, residing in his soul. After the decimation of his family in the hands of a powerful race known as the dreads, he embarked on the part of revenge, leading him to the path of transcendence.

Alicia Rosalyn Von Heist is the youngest daughter of King Edward of Alvannia. She is an illegitimate child born from a maid in the castle her father has fancied. After her mother died when she was young her father took her home and ‘adopted’ her.

In the tenth year after the new era, the world finally came to an end. Zhang Mu truefully waited for his death, but unexpectedly found that he had returned to ten years ago. With his memory about the future, he swore that he would change the calamitous history, saving the earth from being destroyed! Walking dead, zergs, evolvers, and various mutated animals… nothing can stop him! The first step is to retrieve his identity as an era merchant , then find all the treasures he can remember to enhance himself!

- Description from Novelupdates

After experiencing heartbreak from being abandoned, he enlisted in the military.

And then, he became a war hero.