Black Rukh is a dark magical energy that is the polar opposite of White Rukh which is too the namesake part of Rukh (in Japanese: ルフ), the cosmic magic essence that gives life to all living things, and when they die, this essence return to the huge flow (also known as "guidance") of Rukh that gives life to all subsequent beings in an eternal cycle of rebirth called "Fate". The people of Magnostadt have also learned how to use Black Rukh, but only Mogamett so far displayed the use of Black Rukh. It is possible that the magicians in Magnostadt can use it, but they do not exhibit it freely.