An expert sharpshooter who is determined to become the greatest in the universe in any given field. She is an excellent cook, but often causes explosions while cooking, leaving the kitchen completely and utterly obliterated.
Her true name is "Millennium Feria Stargazer" (ミレニアム・フェリア・ノクターン), and she is a relative of Stargazer, the head of Nightmare. Having never met her family before in her life, Millie was unaware of this until the 25th episode, when the Spreader of Darkness, the clone of Stargazer, summons her to kill Kane.
After Kane and Canal disappear, Millie is shown living in the home that Kane and his grandmother once lived in, waiting for their return.