Chris was a survivor, but survival isn't the same as victory. After decades as a mercenary, he ended his first life as a broken man missing an arm, haunted by dead comrades, and serving a world in ruin. But when a mysterious artifact triggers a regression, he awakens in his fifteen-year-old body. He is once again a low-rank foot soldier, but this time, he carries the tactical mind of a grandmaster. This isn't just a fantasy; it’s a systematic speedrun of military history where knowledge of the future is the deadliest weapon on the battlefield.