Shadow Runner, meaning "Unparalleled Shadow," was one of Cao Cao’s favorite and most famous horses, known for its exceptional speed and endurance. This horse played a pivotal role in Cao Cao’s survival during one of the most dangerous moments of his life. While being pursued by enemy forces, Cao Cao was ambushed at Huarong Pass after a disastrous defeat at the Battle of Red Cliffs.

During this chaotic retreat, Shadow Runner carried Cao Cao through treacherous terrain and across rivers, escaping from the clutches of Zhou Yu’s forces. However, the horse was wounded by an arrow, leading to the famous saying: "A hero can do nothing without a good horse, but a good horse can be felled by a single arrow."

Despite the injury, Shadow Runner continued to serve Cao Cao loyally, its endurance becoming a symbol of perseverance and determination, much like Cao Cao himself.