is a completed series of light novels written by Mizue Tani and published in Japan by Shueisha. The story is serialized in Cobalt magazine and illustrated by Asako Takaboshi (Ayuko).

Shueisha has commercially released two drama CDs and a manga adaptation began serialization in Margaret in the September issue in 2008 and ended in the May issue in 2010.

An anime adaptation was broadcast from September to December 2008. A visual novel for the PlayStation 2 was released on April 30, 2009.

Plot

Story The story, set in Victorian Britain, follows the adventures of 17-year-old Lydia Carlton, nicknamed the "Fairy Doctor" due to her understanding of fairies. Her life takes a 180-degree turn when she meets Edgar J. C. Ashenbert, the "Legendary Blue Knight Earl" and his crew on a sea voyage to London. Edgar hires her as an advisor during his quest to obtain a treasured sword that was supposed to be handed down to him by his family.

Characters

Lydia Carlton, the daughter of Professor Carlton, is a 17 year old fairy doctor who was born and raised in Scotland. She has the rare power to see fairies, an ability inherited from her mother. Lydia has green eyes, a trait of those with the gift to see fairies. (Her eyes are green-gold) and a red hair. She is independent and kind, and doesn't hesitate to help others. She ends up working for Edgar as his consultant on fairy-related matters after helping him retrieve the Merrow's Sword (key to him being recognized as the Blue Knight Earl by the Queen of England). Her goal is to become a full-fledged fairy doctor, and frequently places herself in danger willingly when it comes to anything to do with problems between humans and fairies. She appears to have some self-esteem issues, referring to her own hair as "rust-colored" and comparing herself to her mother, who was apparently a woman of considerable beauty. Everyone who knew her mother before she died says they don't look anything alike. Once, in an outburst, she confesses to Paul Ferman she thinks she isn't cute at all, and it's part of the reason why she tries so hard to help in other ways (by working hard). Her physical differences from her parents also lead her to wonder if she is, in fact, a changeling. It is later revealed she is indeed part fairy. Her mother, Aurora, was half-fairy (due to familial circumstances forced the real Aurora to be exchanged with a half-blood changeling.) Because of past difficulties, Lydia dislikes the idea of falling in love and even seems to be afraid of it. When she was a child, she was given a love letter by a boy who - as it turns out later - was dared to do so by his friends, crushing her. She used a "spell" to ward off Kelpie so he would not come near her, as his aggressive advances were troublesome to her. At first, she also rejects Edgar's advances and brushes them off, but as she falls in love with him, she demonstrates substantially less distrust of his confessions of love. Lydia is considered Edgar's fiancée, a status she vehemently denies, despite Edgar's overt courtship of her and multiple fairies calling her that. She obtained this status when she accepted a moonstone ring (previously owned by Gwendolen, the countess of one of the past Blue Knight Earls before Edgar), which effectively meant she accepted his proposal. The moonstone ring apparently has some protective powers of its own; it prevented Lydia's soul from being fully trapped by the fairy world in volume 6 of the novel series, as well as enabled Lydia to break Kelpie's spell on her when he tried to bring her to the fairy world by magic (to prevent her from being hurt in the crossfire between Edgar and the Prince). Though Lydia despises Edgar in the beginning, it is known she has undressed herself in front of him when spilling tea on her dress. When this incident occurs Edgar is outside the bed room door observing Lydia change, which makes him want her more than before for her beauty and personality. Recently, Lydia has truly accepted Edgar's proposal, and afterwards it is shown Lydia has hence been accepted as part of the Blue Earl Knight's family (as Edgar's fiancee). When she takes what should have been a fatal blow from the Blue Earl Knight's sword, she emerges unscathed, proof the sword has acknowledged her as the Knight's family. Following this revelation, she becomes able to form a shining bow from Gwendolen's moonstone ring, and is able to use it to repel Unseelie Court. Strangely, even though he is the Blue Earl Knight, the sword still inflicts physical harm on Edgar. This is supposedly because Edgar's blood has been "dirtied".

Edgar is a flirtatious man in his early twenties with very distinctive ash mauve eyes. When he was young his parents were both murdered and he himself was thought to be dead. As a result, he was shipped to America as a white slave. He was subsequently framed as a mass murderer and forced to flee from America for his alleged crimes. Stripped of his honorable name, Edgar embarks on a journey to find the famed Sword of Merrow. By obtaining the sword, Edgar hopes to assert himself as the "Earl of the Blue Knights" thus acquiring a respectable title and gaining a fabricated sense of honor. In his quest to find the Sword of the Merrow, Edgar captures Lydia Carlton, believing her eyes to be the key to finding the legendary sword. He gradually falls in love with Lydia and is frustrated and confused she continually avoids his advances. He openly shows his love for her, in ways which Lydia often feel are embarrassing. He tells her it makes him uneasy to see her communicate with other men so easily and is unnerved by her friendship with Paul. Edgar was heir to a dukedom (the highest rank in the British peerage) before his family was murdered. He was then captured by an organization headed by a mysterious figure known only as the Prince. There, he was groomed to be the Prince's successor, learning all the knowledge the Prince possessed, including how to ruthlessly make use of the people around him. Later, he managed to successfully flee the organization, taking Ermine and Raven with him, among other supporters. However, on more than one occasion, Edgar has wondered whether he is becoming more like the Prince by making use of the techniques taught him by the Prince in his quest for survival after his escape. Later, it is revealed the Prince murdered his parents to capture Edgar, believing him to be the most suitable successor to the Prince's name. This is because Edgar was of both royal blood, and blood related to the Prince, and would hence easily absorb the Prince's memories. This is quite literal, in that the Prince was a title carried by several generations of Princes. Each generation would groom a new successor by breaking the Prince-to-be's own self-consciousness and forcing him to learn the original prince's knowledge, mannerisms, behavior, etc. to the point that when the Prince transfers the memories from the entire lineage of Princes into the Prince-to-be, the new Prince accepts the memories so naturally that he believes himself to be the Prince. Edgar was also trained as such, but he retained his own personality and will, and was not broken when he fled the organization. After meeting Lydia, as well, he begins to recall his kinder side that had been pushed under in his desperate bid to escape, and becomes increasingly less "Prince-like". He maintains, though, that he cannot fully let go of the knowledge he learned by the Prince's side, because they are weapons that he needs in order to protect his loved ones. Later, in order to save Lydia, he steals the Freya (a red gem created by a powerful wyrm, that is able to absorb and transfer memories) containing Prince's memories. In doing so, he absorbs the memories and effectively becomes the Prince. However, Edgar still retains his original personality, although he is also shown to be deeply uneasy about how long he could keep his own will. He quickly maneuvers events such that Lydia becomes his fiancee. He does, however, maintain relations with other paramours for some time even after claiming engagement to Lydia, which makes her ever more distrustful of his advances. Later, he decides to be truly faithful to Lydia alone. It is shown that as time progresses, he falls deeper in love with her; in the beginning of their partnership, he treats Lydia as a pawn (he uses her as bait without her consent to lure his enemy out into the open, although notably he also attempts to protect her by ordering Raven to trail her). At the time, Lydia mused that she's in an extremely ambiguous position, in that she is enough of an outsider that Edgar treats her as a pawn, but enough of a comrade that Edgar feels an obligation to protect her. However, later, Edgar becomes uncertain of the wisdom of involving her in the battle between the Prince and himself, as he cannot guarantee her safety. It comes to the point that he continuously contradicts himself by wanting to keep Lydia with him, but also wanting to keep her safe by pushing her far away from himself. He is severely possessive, and it has been noted by Lydia that he "cannot tolerate anything that belongs to him being taken away by another". This possessiveness extends to Lydia also; Edgar has been known to become jealous of many men who appear interested in Lydia, or whom Lydia are friendly with. On one occasion, when Raven accidentally saw Lydia dressed in a revealing Arabic costume, Edgar commands him to forget what he saw. Initially, his driving goal was revenge on the Prince for murdering his family, no matter the sacrifice. In order to achieve this goal, he cares little for his own life. After the Ashenbert family's banshee saved him at the cost of her own life and entrusted the key to the land of Ibrazel to him, however, he tells Lydia that his thinking has changed, and now he understands that as the current Blue Knight Earl, even if he does not possess the ability to see fairies, he will persevere and find a way to defeat the Prince as the duty that comes with his title. He also tells her that he will no longer treat the preservation of his own life as cavalierly as he did before.

Raven is 18 years old at the beginning of the series, and Edgar's personal servant. He is Ermine's half-brother. He possesses mysterious green eyes and exceptional fighting skills. It is revealed that Raven was born with a sprite residing within him, and for this reason he was not acknowledged by many. Edgar has mastery over the sprite, and hence Raven. According to Raven, Edgar would never take advantage of this power. And because Edgar accepts him despite his obscurities, Raven is pleased to serve him. When Raven and Ermine were young, they were taken in by Prince's organization. Raven was then trained by fighting masters, but due to the speed at which he surpassed them, and his inability to control his sprite's killing impulses, as well as his own indifference to killing them in the course of his training, he eventually ended up being chained and locked away. This was where he met Edgar for the first time, when Ermine brought Edgar to meet Raven, telling her brother that "she had found his master". While the sprite within Raven was supposed to serve and protect the king of Raven's (and Ermine's) tribe, Raven immediately accepted Edgar as such. It was then that he received the name "Raven", which Edgar gave him to signify that he was to be the master of his sprite from now on, instead of the other way around. It is shown, however, that the sprite's obedience to Edgar is not absolute. When the sprite's killing lusts override Raven's own will, even Edgar is unable to stop it.