This story tells the tale of a young woman whose family passes away. In desperation, she asks a magician to wish them back. However, the wish cannot be granted. She ends up becoming his assistant until she can decide on a wish he can grant. Just what is the most precious possession one must give up to have their wish granted?
A tomboyish, strong girl who is ridden with pain and guilt over her family's death. Right before the manhwa begins, Ryu Jin is forced to stay behind while her parents and older brother Ryu Ui go to Hawaii. She is furious over what she sees as injustice, since the ticket her brother has was originally for her. In her unhappiness, she states that she hopes their plane will crash, but she is distraught when it really does crash and her entire family dies.
After a strange dream in which she is told to seek him out, Ryu Jin goes to see K, intending to wish for her family to come back to life. He refuses, saying it is not within his power to do so. She is unable to make any other wish, and K promptly makes her his assistant, telling her that she is bound by the rukes to stay until she finds a wish to make. This is in fact a lie, as it is revealed in the very next page that he is keeping her there to keep an eye out for her as was requested by her brother and his teacher, Ryu Ui.
Ryu Jin resents K at first, thinking that he is simply a cold, materialistic magician with no decency whatsoever; this is partly because she only sees what he is doing on the surface and does not know the rest of the details, and also because K never seems compelled to explain anything to her or to clear his name. After a while, she begins to see that K's judgement regarding the wishes he grants is not as callous or as cruel as she initially thought; she even stands up for him in volume 5, when a dissatisfied ex-customer expresses the desire for revenge against him.
Eventually, Ryu Jin comes to love K. In volume 7, when she learns that he will soon die, she makes her wish for him to die painlessly.
A mysterious, ancient sorcerer who grants wishes - except those regarding life or existence - to anyone, but at the price of the person's most prized possession. His true name remains unknown since he said there is a curse attached to his name. It is revealed in volume 7 that the so-called curse refers to a curse K himself places on those who laugh at his name, which is supposedly very strange and/or funny-sounding.
Though K is a cranky, cold individual, he usually grants wishes in such a way that they end in the best possible way. He insists that he is an emotionless creature, as he is of a race that knows no emotion, but this seems unlikely because he was taught human emotions 10, 000 years prior to the events in the manhwa by Ryu Ui. Though he would swear against it, he does have a conscience and is willing to accept the consequences of his mistakes.
K's is one of the few non-human races mentioned in the manhwa, characterised by ice-cold skin and a complete lack of emotions. If, however, one of his race were to somehow fall in love, he/she would assimilate with the loved one (i.e., experience the same feelings and ailments). This is visible throughout the manhwa, where K's flamboyant appearance gradually tones down and becomes more casual as he unwittingly falls for Ryu Jin. He only realises this in volume 6, when he catches a somewhat mysterious cold and cannot understand it, until he finds out that Ryu Jin has been ill too for the last few days. However, falling in love is dangerous for K as the assimilation means that he will die if his loved one dies.
K dies at the end of the manhwa, only to return as he was Ryu Jin's most precious possession that she lost when she made her wish for him to be able to die painlessly.
J: One of K's friends and fellow peers, he's apart of a race that when they become too happy, they die. He trained a young woman named Yuri and over the hundred years they spent together he not only fell in love with her but the happiness he felt soon took his life. Like with Yuri, he taught K about human emotions such as happiness and anger. He never taught her about love, for he did now want her heart to burst, but despite that it happened anyways.
Yuri: A young woman apart of the same race as K. She spends one hundred years with J to learn to live as a human being with human emotions but falls in love with him over the period. Because of her race she's tied to J to feel happy when he is, to feel pain when he's hurt, and finally, succumb to death with his death. After J's death she visits K to pass onto him J's ashes before she dies.
D: One of K's friends and fellow peers. She's a bit empty headed and naive but her intentions are always to help others. However, these methods usually backfire and she receives criticism, much to her offense. D has a habit of trying out spells by using K, usually resulting in K's misfortune and her being told he doesn't want to see her face for one hundred years. One incident involved K being locked in a tree for two years because she couldn't make the escape spell work. While she wants to gives K his "spring day" and constantly chases after him what she truly wanted was Y's praise. While her love potion succeeded in making K fall in love because she had been experimenting on humans they nearly killed her to "share her equally" between them but Y sacrificed himself to save her. The incident has assumably made her more cautious of magic. In volume 6, it's revealed her and Y got married.
Y: One of K's friends and fellow peers. He was once a great magician capable of even rising the dead who succumbed to greed and power. When he began to be ostracized and feared by the people he created a love potion so they would love him but that made things worse when humans began to fight over him. Rather than give up his power he went to the desert to be alone. To his horror, the love potion caused the sun itself to fall in love with him and caused the sun to move closer to earth, eventually to crush earth. However, Jin's brother found him first and showed him to hide himself from the sun in exchange for Y becoming his third pupil. Y is usually covered in bandages and is often mistaken for being an old man. Because of his fondness and worry for D he asks K to transfer his magic and knowledge to D, leaving him a normal human. Though he's killed during his effort to save D he's resurrected by the spell he transferred to D. It's revealed in volume 6 that he and D got married.
Ryu Ui: Jin's brother and K's teacher. He's a guy with a twisted personality and a bit narcissistic. He died in the plane accident that killed Jin's parents too but it's revealed that Jin was supposed to die in the crash but he took her place. He was supposed to die at age twenty but made her miss the trip and made a wish to K to take care of Jin for him. Apparently he's been reborn multiple times.
7: One of Ryu Uli's pupils. Not much is known about him, except that he's spoken of with disproval by the other characters. D describes him as the "weird" one and Y makes a comment about how 7's help comes with a "too heavy" price. In volume 5 Y warns K to watch out for 7 and that he had a "new face". He makes his first physical appearance in volume 7 and reveals his power is to make someone's worst fears come true. He also has a deep grudge against K.