This card is the Dark version of "Archlord Zerato", almost as if he was corrupted after ascending to power as the Archlord.
This monster's appearance resembles the stereotypical portrayal of Fallen Angels and demon lords.
This card's Japanese name actually puts it among the Fallen Angels.
The above can be inferred by the artwork on the card; what appears to be the ruins of "The Sanctuary in the Sky" appears in the background of this card. It is possible that he may have been responsible for the destruction of the sanctuary.