Yuiki Yaya

Known as the Ace Chair of the Guardians, Yaya is a childish girl who is also the group's baby. She is one year junior to Amu and is very hyperactive. She mostly plays with Kukai who is serving the Jack's chair. It was found out that Yaya was a ballerina in episode 6 which also Amu's first transformation with Miki. Yaya has a younger brother named Tsubasa, in episode 31. But Because Yaya felt the attention her parents give to her little brother, she became jealous of him. But she felt her responsibility as an older sister. So, when baby Tsubasa got sick, older sister Yaya knew that she had to bring him to the doctor. Her Guardian Chara was Pepe, a baby-like chara which is born because of Yaya's desire to remain her childish nature. Her first transformation with Pepe was in episode 41, which she transformed into Dear Baby.

Souseiseki
4th Rozen Maiden Doll, Souseiseki, is the only Rozen Maiden Doll who is created to have a masculine form of dressing. She is the twin sister of Suiseiseki, the 3rd of the Rozen Maiden Dolls. Compared to Suiseiseki, Souseiseki has a sharp way of speaking which is compared to Shinku. Instead of using "watashi" or "jibun" as first person pronoun, Souseiseki uses "boku", which is noted to be masculine form of speaking. Her Artificial Spirit was called Lempicka, which takes the form of a gardener's tool, the shears, her fighting tool. She was later seen on episode 8. In the anime, her medium was a lonesome old man who lost a son. He took Souseiseki, who he sees as his late son, and Suiseiseki in. But because he sees Souseiseki as his late son, Souseiseki was then forced to stay with him and give him more attention, which is the reason for Suiseiseki's parting away from her. Souseiseki and Suiseiseki lived together again in the end of the season.

In the second season, traumend, Souseiseki made a decision to leave Suiseiseki to Jun and mostly visits her to help. Later in the season, after Souseiseki learned the importance of the Alice Battle to their father, Rozen, she then decided to finish the battle and win Alice and said that she will fight anyone who interferes in her way. She was later on defeated by Suigintou, who took her Rosa Mystica, and died in Suiseiseki's hands.