She is also known as the Witch of Miracles, and greatly resembles Rika Furude from Higurashi no Naku Koro ni. Her name also suggests some connection to Rika's "alter-ego" Frederica Bernkastel (which is hinted when Bernkastel quotes herself saying Rika's trademark "Ni~pa" sound). It is said she resides in a world where concepts such as fate and probability can be visualized. Despite this, she has a pretty twisted personality and described herself as the "cruelest witch in the world."

Unlike other witches she has lifeless eyes. She appears to see Beatrice's game to solve her boredom, and unable to stand seeing the player getting tortured by Beatrice's game, she assists the player by giving some hints around the workings of the game. Her "Magic of Miracles" allows her to reset a desperate situation as long as the probability of a favorable situation is not equal to zero (Similar to Hanyuu's power to reset time).

She wants to defeat Beatrice, regardless of the means used for this objective. Throughout Umineko no Naku Koro ni, she maintains an icy and aloof calm in most situations, though by the end of Alliance of the Golden Witch and throughout Umineko no Naku Koro ni Chiru, she is shown to be just as impish and playfully cruel as Lambdadelta.