|Artificial spirit||Lempicka (レンピカ)|
|Medium|| Kazuha Yuibishi (first manga series)|
Jun Sakurada (second manga series)
Motoharu Shibasaki (anime)
|Eye color||Green (right), red (left)|
|Family|| Rozen (father)|
|Debut||Rozen Maiden episode 8 (anime)|
|Voice actor||Rika Morinaga|
|English voice||Julie Ann Taylor|
Souseiseki (Japanese: 蒼星石, German: Lapislazuli Stone) is the fourth doll of the Rozen Maiden series. She is the younger twin sister of Suiseiseki.
Souseiseki has a much smaller role in the manga than the anime, which is merely a plot device to continue the story. Her master, Kazuha Yuibishi, has been seeking revenge for the woman who eloped with his brother, which led to his death. Souseiseki is needed for this task, for her powers involve the ability to simply enter one's dream world and destroy the person's life tree, and life force of the person himself. However, since Souseiseki could not alone achieve this goal, she appears to Jun's group asking for Suiseiseki to help her. She ends up fighting Suiseiseki to gather the two gardeners' tools, the shears (which is her own weapon) and the watering can, which together could affect an individual's soul tree. She eventually realizes, however, that it is her master's heart that needs to be freed, and sacrifices herself to do so. The dolls present are shocked by Souseiseki's actions and Suigintou uses the confusion to snatch Souseiseki's Rosa Mystica, enraging both Shinku and Suiseseki. Kirakishou later uses Souseiseki's body to materialize in the not-wound world. However, before she can completely materialize, Jun of this world unexpectedly enters a contract with Souseiseki's ring, causing the body to reject both Kirakishou's Rosa Mystica and essence. In the latest chapter, Suigintou has returned Souseiseki's Rosa Mystica and told her to keep it until she finds an answer to the Alice Game.
In the Rozen Maiden anime, Souseiseki's plot is completely different. She lives with the Shibasaki family, trapped in a sort of dilemma. The watchmaker Motoharu has gone delusional after the death of his son, Kazuki, and his wife, Matsu's subsequent fall into a coma. Souseiseki does know the solution to this problem, which is to awaken Matsu and bring Motoharu back to his senses, and has frequently visited Matsu's dream world, but has found nothing, for it consists of only a pure white, blank space. With the loss of his family, Motoharu believes Souseiseki is his alive son and hence is overprotective of the doll. Suiseiseki had begged for her twin to run away with her to the Sakurada household, but Souseiseki put her duty to her master first and stayed. Unfortunately, this did come with a price. In order for his "son" to never leave him, Motoharu decided to make Souseiseki sleep on the floor, tied to the bed, rather than in her case. Because the Rozen Maidens must sleep in their briefcases to dream, Souseiseki is quickly losing her emotions, doomed to eventually become a shell of her former self. Suigintou intervenes, hoping to defeat the other sisters in one scheme, by stealing Lempicka, Souseiseki's artificial spirit, and taking control of Motoharu's dream world to lock Souseiseki inside. Jun, Shinku, Hinaichigo, and Suiseiseki arrive to rescue the fourth sister, during which Shinku and Hinaichigo divert Suigintou's attacks for Jun and the twins to escape. This time around, they enter Matsu's dream world and encounter Kazuki's spirit, who has been keeping his mother with him for his own happiness. Souseiseki convinces the boy to let go of her so that both his parents can be happy. When the group confronts Suigintou, Suiseiseki sacrifices her artificial spirit, Sui Dream, to satisfy her, and they return to the real world to witness Motoharu and Matsu's reunion. With the appearance of Barasuishou, the (later deemed false) seventh sister, Souseiseki interprets this as a sign from Rozen to begin the Alice Game, though her sisters are content with their happiness and do not wish to fight. Inner conflict strikes, with the fourth sister torn between her happiness and her duty. (In the fourth character drama CD featuring Souseiseki, she experienced consecutive dreams of being attacked by Suiseiseki, joining a tea party with all the sisters in peace, and finally, being told by Laplace no Ma to choose her destiny behind one of two doors. From previous words of advice from Shinku, Souseiseki destroys the doors, claiming that her destiny is hers to decide alone.) After a trip through the N-Field, where she witnesses illusions of a weeping Rozen, Barasuishou says that their Father is in sorrow for his daughters will not decide who is his Alice. Truly determined to grant her Father's wish, Souseiseki declares to her sisters that she will eventually fight them in the Alice Game, and promptly disappears from them. When Barasuishou and Suigintou turn the real world into the N-Field, Shinku, Hinaichigo, and Suiseiseki are drawn into the battle, with Souseiseki reappearing to fight the Suigintou. Despite her twin sister's pleas that the two of them were not meant to harm others, Souseiseki answers that the Alice Game is still their fate, and rises up to Suigintou again, only to be defeated and fall to her end. Souseiseki becomes the first doll to lose her Rosa Mystica, and when it appears for everyone to see, Suigintou snatches it while Suiseiseki rescues her body. Souseiseki is returned to her briefcase to continue her deep sleep, and when the series is abruptly cut off, her fate is still unknown. Laplace's Demon is seen holding two Rosae Mysticae, which may belong to her and Hinaichigo. Souseiseki narrates to Jun the story of Shinku and Suigintou's relationship. During the flashback to 19th century London, Souseiseki and Shinku are engaged in a violent duel for the Alice Game, their strengths so strong that much of the town is destroyed in the process. Suiseiseki suddenly interrupts the fight, warning that too much strength has been weakening the twins' medium. The fight is postponed and is later situated in Souseiseki's N-Field, during which Suigintou intervenes, having curiously followed Shinku, wondering what she was doing. Suigintou's introduction as the first sister makes Souseiseki realize that Suigintou is yet more competition in the Alice Game, and promptly charges at her, slicing the harmless doll's body in half, despite Shinku's pleas.
Suiseiseki's younger twin, Souseiseki is the polar opposite of her sister, even in eye color - while Suiseiseki's mismatched eyes have the right red and the left green, Souseiseki's eyes are right green, left red. Her appearance is not only the most masculine of the dolls, but her speech is also noted to be of the masculine form. She dresses like a boy, and the fact that she refers to herself as "boku" instead of gender neutral pronouns like "jibun" or "watashi" makes her even more boyish. Souseiseki has shoulder lenghth auburn hair and wears a blue caplet over a white shirt, blue pants and a top hat with short black boots.
Souseiseki possesses a sharpness in her speech that is similar to Shinku's, attacks ruthlessly in combat, and does not tolerate sub-par actions. Although Souseiseki's character is the complete opposite of her elder twin's, they are rarely seen apart from each other. Souseiseki is slightly more eager to participate in the Alice Game, due to a sense of duty to Father. Souseiseki often becomes the voice of reason whenever Suiseiseki does something mischievous, but most of the time she is caught up in the trouble her twin sister makes. She is quite
serious most of the time, but she's still very kind hearted.
Souseiseki's artificial spirit is the light blue colored Lempicka (レンピカ), who is used to summon her weapon, the gardener's shears. In combat, they are used like a sword to block and parry attacks. In the dream worlds of humans, Souseiseki uses the shears to cut away the brambles that represent one's memories. While ideally, only the dead roots could be cut away, freeing a human of his or her burdens, the good memories could be cut off as well, killing the person inside.