Kuroi Marie

While seemingly "Marie Antoinette Alter", Black Marie is actually Erice Utsumi's Dread Spirits taking the form of Marie in response to Erice's connection to Louis XVII and her guilt over killing him. She seeks to drive Erice into despair, and says that deep down it's what Erice wants.

She initially looks like, and is believed by everyone else to be, the real Marie Antoinette, but as the story goes on she loses Marie's usual upbeat personality. After being exposed by the real Marie, she then pretends to be another side of Marie's personality. Her true identity is revealed when Ritsuka Fujimaru realizes she couldn't know about Louis and Erice since Marie wasn't present for their encounter.