Famous quote: “When they’re alive, you can enjoy watching them struggle. When they’re dead, you can enjoy tearing out their guts. Tales are things you get to enjoy twice.”
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.
Frederica is an omni-present being surrounding the Higurashi universe. She is the writer of the poem about Rika’s struggle to escape the fate of June 1983, giving hints about each arc.
She likes playing with time and events, as seen in puzzle piece #52 and the end of the second season of the anime, entering an alternate world and stopping Miyoko’s (Miyo Takano’s) parents from dying. She even has an intention of making a world where Rika’s or Satoko’s parents did not die, or pairing Keiichi with various girls.
Although she claims that she is not Rika, it’s implied that she is the collective mentality of the several thousand reincarnations of Rika. The pronunciation of Frederica roughly resembles Furude Rika, and Bernkastel is well known for its wine. Plus Rika says herself in Higurashi no Naku Koro ni Rei “I’ll have to stop being the witch Bernkastel,” after getting confused with dreams, it can be assumed that this choice separates Bernkastel and Rika and makes Rika fully human. This can also be seen as a prove that they’re the same person/Bernkastel’s origin are Rika’s memories.
She is also voiced by the same seiyuu as Rika Furude, further enforcing the theory.