Last Ruler Of The Empty Throne - Chapter 20: Limited slots

Cha Myung-jun, a sergeant who neared the end of his military service, found himself confined in the Ministry of National Defense’s bas**ent for over three decades due to his newly awakened abilities, just before the outbreak of war. Spending thirty years as the world’s most formidable blacksmith, wielding nothing but hammers, he skillfully outwits the watchful eyes of the Ministry of Defense to serve the war effort and reset the course of time. Now given a second chance at life, can he lead a successful campaign to avert humanity’s downfall and secure its salvation?

Until the time of him becoming the master of the lowest rank in the order of rankings, the lonely side of his life without luck was changed.

The unparalleled Demon King Ye Xuan, who was able to heal the death or the living alike and holder of the medicine Holy Scripture, was betrayed and killed by his fellow Demon Kings. But he reincarnated into the body of Ye Xuan, the prodigal son of the Ye family and vowed to himself that he would return to his peak and take back everything that belonged to him!

- Description from Novelupdates

Karl Adelheit, a self-proclaimed ordinary student returning from military service.

And a nobleman who enlisted as a soldier and received Medals of Honor.