Master Smith Under Ministry of National Defense

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? — Description from novelcodex.org