Protecting the National Treasure but Accidentally Traveling Through Time

The current generation of talented people fought a bloody battle with the Japanese country to protect the national treasure "Hongjun Pagoda"... And were killed because they were outnumbered. But due to an accident, he traveled to another world and became the only grandson of the Grand Marshal of the Dragon Kingdom... But his father and brother died unexpectedly in battle. My uncle's legs were disabled in the war, and my grandfather is old... See how he takes revenge and reaches the pinnacle of another world, becoming a king of his generation! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.