Lambdadelta, the Witch of Certainty (絶対の魔女ラムダデルタ Zettai no Majo Ramudaderuta?) used to be known as the most powerful witch in the universe, but was defeated by Bernkastel (whom she cares for but hides her feelings) in "another game". She is also known as the Witch of the Absolute and her "magic of certainty" allows her to kill anyone with an absolute result.
Her goal is to "trap" Bernkastel by making the game between Battler Ushiromiya and Beatrice last for eternity, thus forever involving Bernkastel in the game. She has lived for a thousand years. As a witch, she embodies the concept that "hard-workers are rewarded", and is very much respected even by human beings.
She doesn't flee from the human concept of a witch; hence, the power of hers, which is respected by human beings, is immeasurable. However, she is whimsical about whose efforts she will reward and, in many situations, the person who can please her more will be able to receive her smile. Her tremendous and swiftly fierce power makes any kind of witch surrender in a moment. However, she seems to be reckless and it was thoroughly read by Bernkastel & She loves Bernkastel very much, but chooses to hide it.