Rika Bernkastel, known as Bernkastel (ベルンカステル) in 'Umineko no Naku Koro ni', is a mysterious and enigmatic witch who observes and manipulates the events of the story. She is known as the Witch of Miracles, capable of creating miracles as long as the probability is not zero. Often portrayed as calm and emotionless, Bernkastel plays a major antagonistic role, orchestrating games and challenges for other characters, especially Battler. Her true motives remain ambiguous, adding depth and intrigue to the series.