Reasons to Become a Ghost

Lord Sima, who frightened the enemy and was known as the God of War during the Warring States Period. He was extremely skilled in mobilizing troops and deploying generals on the battlefield for ten years without a single defeat. He never expected to die miserably. The hatred and pain, love and regret he experienced during his lifetime became the reason why he had to become a ghost. Can the lost feelings of those years span thousands of years, from the past to the future, and be picked up one by one?