Human Spirit of Darkness
The Human Spirit of Darkness was created from Ancient Sphinxmon. It was found at some point by Cherubimon, who corrupted it into the Corrupted Human Spirit of Darkness and forced it on Kimura Kouichi, turning him into Duskmon. The spirit revealed its true form after being purified through Minamoto Kouji's D-Scanner, when Kouichi accepted that neither he nor the spirit was inherently evil. It then allowed him to spirit evolve into Löwemon.
(Note: Is called Spirit of Darkness L in the TCG.)