A powerful sorceress and the primary antagonist of Murder Princess. She channels power from a jewel below her neck to her baton, which she then casts with. Shooting lightning is her primary attack but she can also coat her hands in purple flame and raise powerful defensive wards. She manipulated Professor Akamashi into using Lost Technology and turns Kaito into her ally in her quest for the power of the Teoria.
When Falis was a child, Cecilia destroyed her village and killed her parents while she watched. The only reason behind the attack was so Cecilia could test her power and Falis's village was simply the first she had come across. She shows no regret in doing this, saying that great power is for great people to use.
Falis is able to kill her when she shatters Cecilia's necklace, revealing her weakspot - a jewel below her neck. She shatters the jewel with her katana. Without the jewel to regulate the power, Cecilia is vaporized when her power is released in an explosion of purple light.
Voiced by Megumi Toyoguchi (Japanese), Wendy Powell (English)