It is unknown who he was before his death, from which race he came or even in which Era he was born. At some point he came to the Necropolis and died there. He became one of the many Ghosts and worked as a Ferry Handler at Nightsea.
One day Dark Crow met him at Nightsea and was impressed with his talent. Dark Crow believed that he can become an Immortal Emperor and helped him to escape from the Necropolis, but didn't help him any further due to the promise to the Ancestral Flow's Master.
Future generations, including his own Imperial Lineage, knows very little about Ming Du's origin. Most people believe that he was Ghost Immortal, while others believe that he was either a boat-rowing ghost of the Underworld River or ghost from the Nightsea at Necropolis, that obtained a great fortune, returned to life and escaped Necropolis. The Nether Crossing Swamp denies these theories, even though the last of them is the real truth.