Lambdadelta is a main character in the series Umineko no Naku Koro ni. The Witch of Certainty, used to be known as the most powerful witch in the universe until she was defeated by Bernkastel. She is also known as the Witch of the Absolute and her "magic of certainty" allows her to kill anyone with an absolute result. She can travel through the dimensions. Her birthday is 20 June.
- Bernkastel is whom she cares for but hides her feelings.
- Her wish: To be with Bernkastel for all eternity.
- She slept next to Bernkastel.