Transmigrating to Fight the Japanese, I Get Stronger by Pampering My Wife

He was a special forces soldier in the 21st century who transmigrated to 1937. To his surprise, he activated a System for fighting the Japanese invaders. From then on, he began his resistance and mission to save the country! The outlaws of the martial world willingly pledged themselves to him and called him Big Brother! Military and political bigwigs from every faction tried to win him over and showed him the same respect! But all of that was fleeting, and all of it was just a means to an end. Only driving out the invaders and restoring peace to the land mattered. That was his true mission!