^?, Mercury Lampe, Mercury Lamp) (Spelled Suigintoh, and then later changed to, Suigintou in the TokyoPop translated manga.)

(early drama CD)

), Suigintou has no inhibitions when it comes to the Alice Game. She will use any method available to her, regardless of how brutal it may be, to reach victory. Although she avoids socializing with all of her sister dolls, she has a particularly bitter hatred for Shinku. However, upon meeting Megu, her medium, Suigintou's attitude and motivations begin to shift; she begins to feel a strong affection for someone other than "Father", and a will to fight for something other than the honor of becoming "Alice", the perfect girl. Her love for "Father" is actually the purest amongst all of the seven dolls. Suigintou's desire to protect Megu begins to even overpower her wish to meet "Father," and she hopes to use the collected Rosae Mystica, not to become Alice, but to heal Megu's heart ailment instead. However, Suigintou fails in this endeavor, discovering to her horror that she has used up Megu's energy. She also hates being called "junk".

Initially, Suigintou's will to exist was so strong that she was able to move without actually possessing a Rosa Mystica. Suigintou did not consciously make a contract with Megu, rather, Megu came upon Suigintou as she was reawakening. Suigintou's strong sense of independence, as well as disdain towards humanity, had her avoiding the perceived weakness of having a medium. She is also the only Rozen Maiden to have been defeated and revived three times.

Suigintou has a number of unique traits and flaws amongst the seven Rozen Maidens. In the anime, she is missing a part of her torso; Shinku explains at one point that before Suigintou was completed, her design was erased, but gives no further explanation as to why or how. In ouvertüre, it is shown that Rozen abandoned her half-completed form in two parts on his worktable. She was never assembled — although her clothing was completed — and as such, not initially given the life force that is a Rosa Mystica. It was her love for Rozen that brought her to life, and she crawled off of the table to seek him out. Rozen does later provide her with a Rosa Mystica, only after she is sliced in half by Souseiseki and presumably fated to fade out of existence. Curiously, after Suigintou is destroyed in battle by Shinku at the end of the anime's first season, she is restored midway through Rozen Maiden träumend. The identity of the person responsible for her restoration is never revealed, however it is strongly implied to be Rozen. In the träumend finale, she tells Shinku that "Father" had told her that even with her flawed body, she is also entitled to a part in the Alice Game. Later, Rozen is seen lovingly fixing Suigintou's neck ribbon as she sleeps, and even grips her gently around the waist afterwards, implying that he has mended her incomplete body.

In the manga, her body is flawed by wings — notably, she is the only Rozen Maiden with them — that have ravaged her back with cracks. Despite these flaws, her love for "Father" and willpower is so strong that she can use her powers independently of a medium.

Along with her artificial spirit, Meimei, Suigintou's weapons are her ragged black wings. With their arrow-like feathers, she can conjure up a shield, a large sword, or even twin black dragons. Suigintou can also create destructive blue flames as a last resort in battle. Suigintou's varied abilities, particularly when combined with her savagely cunning nature, make her a strong player in the Alice Game.

In Rozen Maiden ouvertüre, Suigintou and Shinku are shown to have been friends, but the friendship sours significantly after Suigintou discovers that Shinku was only her friend out of pity for her incomplete existence. It is also revealed that Rozen abandoned her without a Rosa Mystica (which she later acquires) and started moving towards her affection for him. When Megu shows Suigintou a bouquet of bright red roses, Suigintou destroys the bouquet, indicating that she either hates roses as a whole, or that she particularly dislikes bright red roses, since Shinku uses bright red rose petals.

In the manga, Megu and Suigintou seem to have a stronger "bond" than in the anime. Megu was also the reason Suigintou traveled to the alternate dimension and subsequently declaring a truce with Shinku so that the two may work together to bring down Kirakishou, only to be trapped in a room encased with crystals later with the other three Rozen Maidens. Kanaria finds them, however, and frees them. To return to their original world, the revived Souseiseki affirms that only she and Suiseiseki together can return everything to the way it was. Reluctantly, Suigintou agrees to return Souseiseki's Rosa Mystica to let them combine their powers. After the order started returning to its original state, the Jun from her world arrives with Shinku's body and Hinaichigo's Rosa Mystica. Seeing Hinaichigo's Rosa Mystica willingly guard Shinku's body makes Suigintou question her own motives, and when Souseiseki readies to return her Rosa Mystica, Suigintou breaks their agreement, confirming that she will come to take it again once she thinks things through.