The Obsidian Lord (Japanese: 黒曜の君, Kokuyou no Kimi) is the major antagonist in the Mai-HiME anime and manga series.
He exists through inhabiting the bodies of his hosts and working through them for his own ends. In the anime, he is served by Nagi Homura.
The winner of the HiME Carnival is given the opportunity to marry him.
In the anime, the Obsidian Lord resides in the body of Reito Minagi, the Vice President of the Student Council.