Lambdadelta (ラムダデルタ Ramudaderuta) is the Witch of Certainty and Beatrice's sponsor who has come to observe her game. She first appears in Turn of the Golden Witch. The Witch of Certainty, who has lived for a thousand years. She embodies the idea that "hard workers are rewarded" and is revered even by humans. Though she is a witch, she does not stray far from the concepts of humans. For that reason, her power as one worshiped by humans is incalculable. However, she is fickle about whose efforts she chooses to reward, and in many cases, she bestows her favor upon those who entertain her the most. Her immense, swift, and terrifying power can make any witch surrender in an instant. However, she is often reckless, and Bernkastel was able to take full advantage of that. Lambdadelta appears as a girl in her teens with short, blond hair and medium sized breasts. Her eyes are amber in the original visual novel and Pachi-Slot and red in the anime and console adaptations.
She wears a pink hat and dress and white-and-pink-striped stockings and shoes. Her dress is adorned with pumpkins and pinkish-red bows, some of which are candy-shaped. She also wears black long gloves. Lambda's defining trait is how motivating she is. She always wants to have fun, even if the means to that end seem contradictory to her role. Lambda is playfully cruel and doesn't care what kind of suffering others go through so long as it entertains her, though she occasionally shows compassion. This is exemplified in Alliance of the Golden Witch where she takes Beatrice's side but tries to make Battler stand up and fight when he loses faith in himself. Lambda is arrogant, having declared herself the strongest witch in the universe at one point and claiming that she's had historical buildings erected in her honor after granting people's wishes. On the other hand, Lambda isn't very diligent. In End of the Golden Witch, her records for the Court of Illusions, which she oversaw, are just several lines long as opposed to Bernkastel's thousands of pages. Lambda also has shades of idiocy, where she refers to herself as "super paper", a seeming acknowledgment of her thick-headedness, in reference to the rock-paper-scissors rivalry she has with Bern and Beatrice. Lambda's stupidity may just be an act however, as she will rarely take on a serious tone of voice. At other times, she remembers her Logic Error and breaks down. As the Witch of Certainty, Lambda can grant wishes and make them succeed as a certain fate, however she typically grants this boon to people that already have the determination needed to make their wishes come true.
Lambda can also use Red Truth.
For direct combat purposes, Lambda can create black holes and candy bombs. She can turn objects and other people, including herself, into konpeitou candies. Lambda can also use Red Truth. Long ago, Lambda was a Human. She was trapped inside of a logic error, being one of the few witches alongside Bern to succeed in solving one. It's implied she was responsible for Bern's creation when she trapped her in one of her own games. Bern later defeated Lambda, alluding to this game being created from a "firm fate". At some point, Lambda met the human form of Beatrice and took great interest in her game board built around Rokkenjima, granting her witch powers in exchange for borrowing it to trap Bern. The extra arc Memoirs of the expounds upon this in that she granted a girl's wish for certain determination to become a god at some point in the past. The result of this wish is supposed to have created a new witch for Lambda to play with. Lambda loves Bern and has a great interest in her.
She wants to have a mutual understanding with her since they've both suffered through logic errors in the past. According to Whose Tea Party? Bern used to be much different and started opening up when Lambda started playing with her. The two witches often banter with each other through cruel yet lewd remarks. Bern sometimes loses control of her emotions, and so Lambda has to keep her calm. Lambdadelta is Beatrice's Witch Guardian and Beatrice is the Miko of Lambdadelta. During the conversation about witch powers in the? Legend of the Golden Witch, Bernkastel says Lambdadelta might have a good compatibility against Beatrice since she would be able to kill Beatrice's "endless" nature. It is later revealed that Lambda bestowed Beatrice with witch powers when the latter was a lowly human and now acts as her witch guardian. Lambda doesn't really see Beato as a friend however, and won't hesitate to get rid of her if she disappoints. This is exemplified in End of the Golden Witch where, after Beato surrenders and falls comatose, Lambda continuously mocks her by asking her to speak if she has any problems and acting ecstatic when she doesn't. Lambda is an opponent to Battler by proxy of siding with Beatrice.
Lambda prioritizes having fun and, despite her antagonizing Battler a lot, she will give him rousing speeches when he loses faith in himself and keep Beato's game going, as seen in Banquet of the Golden Witch and Alliance. In End, Lambda becomes Battler's witch guardian when he uncovers the truth of Beato's game and names him the new Golden Witch. From this point forward, Lambda does a lot more to help Battler prove he truly understands Beatrice and mediates some of his games. She still takes a passive stance during Battler's other conflicts in later arcs, but she comes around and gives assistance after seeing his determination. Lambda is also an opponent to Ange, similar to Battler. However, Lambda sees value in Ange as a tool to help her stay with Bern forever. She tries convincing Ange to become her piece instead of Bern's and stall the game for as long as possible, but it fails. Lambda considers Ange a failure after this and is not very interested in her development in later arcs, as seen in Requiem of the Golden Witch when she tells a distressed Ange to pipe down as the true events of the Rokkenjima Mass Murders are playing out. However, in Twilight of the Golden Witch, Lambda comes to sympathize with Ange and names her and the rest of the Golden Land residents as her mikos, fighting on their behalf.
Beatrice invites her to bet against Bern for her victory.
Lambdadelta's name is first mentioned in the? She is said to have been dethroned by Bernkastel alone in the past and "terrifying because of her cruelty". Lambda first appears in the? Beatrice invites her to bet against Bern for her victory. She offers to help Beatrice while planning to take revenge on Bern for defeating her. After everyone else leaves, Lambda gives Battler a rousing speech and encourages him to save Rosa from Beatrice's torture and get back in the game. Lambda gives EVA-Beatrice the recommendation needed for her to become the new Golden Witch and becomes her guardian. She attends the coronation ceremony. In the Tea Party, Lambda shows annoyance that Bern's new piece Ange suddenly barged into the game board without warning. She later has a private talk with Beatrice and shows disdain that she isn't trying to win. Lambda reminds Beatrice that she became a witch in exchange for Lambda being allowed to use her perfect game board. If Beatrice falls short of victory then Lambda won't hesitate to take away her powers and throw her into the worst Fragment. Lambda tells Ange in private that Bern has tricked her.
Even if Ange were to stop Beato's game and set her family free, they won't return to her own future; they will return to a six-year-old Ange of a different Fragment, while this 18-year-old Ange is just a piece and will disappear when Beato's game ends. She also mentions Bern's promise of finding a Fragment where Ange was living happily with her family but couldn't find it, and claims that such a thing doesn't really exist. Lambda gives Ange the offer of becoming her piece instead, with the goal of keeping Beato's game running for as long as possible; if Ange accepts, she can stay with her brother forever and will be allowed to reveal her identity while Lambda traps Bern. Beatrice decides to abandon the game, believing that Battler is unfit to fight her; neither side will be able to make a move, and so there is no winner or loser. Lambda tries to convince Battler to prove his qualifications, but he is unable to and soon disappears. Beato abandons the game board, and Bern leaves with Lambda chasing after her. Beato's later forced to return to the game board after intervention from Ange.
Lambda shackles her to a chair, intent on keeping her there and watching over her for eternity until she wins the game. Battler also comes back thanks to Bern and manages to regain his spirit and qualifications, but Ange sacrifices herself for it and is torn apart. Lambda comments on the sad scene as it plays out. In the???, after Battler and Beato's big debate, Lambda and Bern lie in a bed and talk about the game. Lambda reveals she set the rule about Ange not giving her name, feeling that she and Battler would demolish Beato otherwise. They also mock Battler's theories, with Lambda correcting some of them in red truth. Bern and Lambda talk about how much they see Beato as their plaything and declare on their titles that Blessed will lose for all eternity, and a miracle will certainly not occur. Lambdadelta serves as the new Game Master in the 5th game. She hates boredom as much as Bernkastel, and depending on the situation, she may become either an enemy or an ally to Beato or Bern. Beato falls comatose, having given up on the game still, and Lambdadelta wants to take over as Game Master for her. Battler won't allow it since this game is supposed to be between him and Beato. Lambda promises that she'll arrange the game the same way Beatrice would, insisting that it will help him understand her better. Bern threatens Battler with making the Fragment of Ange being sad in the future a reality, and Battler reluctantly acknowledges the game but says Bern can substitute for him if Lambda's going to replace Beato.