Bernkastel

From Worldsofharuhi

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. She appears to see Beatrice's game to ease her boredom. 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. Like Lambdadelta, she is a Voyager: a witch able to move to the territory of other witches without losing her power.

Worlds of Haruhi Suzumiya

Bernkastel traveled into Haruhi's world while searching for a way to ease her boredom. She finds Haruhi’s powers intriguing and decides to try something interesting with Haruhi’s world. At the end of the summer vacation, she indirectly convinces Haruhi to think “I don’t want Summer Vacation to end.” Because of this, summer vacation is repeated endlessly. Bernkastel enjoys how rest of the SOS-Brigade fails every time to convince Haruhi to stop repeating time.

Endless Eight Arc

After realizing Bernkastel is behind the repeats, Alan slides into Meta world, where he can gain audience with the Bernkastel. Obviously Alan asks Bernkastel to stop this; however Bernkastel tells him that nothing can be done because it’s Haruhi’s power that is causing the repeats, not her. Bernkastel compares this situation not as a game where two players play in, but a puzzle that single person tackles. Bernkastel encourages Alan to solve this “Puzzle” and tells him to not to bore her.