The Emperor of Darkness (Yami no Teiou 闇の帝王) was a character/supervillain/warlord from the manga and anime series Great Mazinger. It was depicted as a large flaming entity. As the Emperor of the Mycenae Empire, he was the true enemy behind the Great General of Darkness and the Great Marshall of Hell. His defeat marked the end of the Mycenae Empire. He is the only survivor of the final battle in Great Mazinger because he never was with his troops. He survives the series too. The only story where he is finally killed (accidentally by Koji Kabuto after his offer to help Duke Fleed against Vega) is the manga version of UFO Robo Grendizer drawn by Gosaku Ota. In Shin Mazinger Shougeki! Z Hen, his true identity is the deity Hades who came from the original planet of the Mycenae Empire and an enemy of Zeus. He took the identity of the Great Emperor of Darkness after Zeus thrown him a Rocket punch of his own and sink along with Bardos Island.
In great Mazinger his voice was done by Hidekatsu Shibata who was also Zenon in Devilman TV, Enma-Daio and Kusari-Gama in Dororon Enma-kun, Emperor of Darkness and Kenzo Kabuto in Great Mazinger, Geronimo, Baron Ashura male and Kenzo Kabuto in Mazinger Z, Baron Ashura in Mazinger Z Vs. Devilman, Mazinger Z Vs. Dr. Hell, Mazinkaiser holy cr-p he was geese howard in the fatal fury anime!! Lol he played God in In The Beginning - The Bible Stories. weird as he was devil Z in transformers super god masterforce.
In Shin Mazinger Shougeki! Z Hen he was voiced by the awesome Kenji Utsumi who was Raoh in Hokuto no ken, Kaioh in Hokuto no ken 2, the dragon in dragon ball/z/gt, Alexander Louis Armstrong in FMA, Ophisto Bazooka in Hanappe Bazooka, General Juuma in Mazinger Z vs. The Great General of Darkness, Odin in Saint Seiya, Emperor Gore in Shin Getter Robo vs. Neo Getter Robo, Vega(m bison(dictator)) in Street Fighter II V and Geobaldi in Outlanders (OAV)