Yaya (夜々 (やや), Yaya) is the yandere to Akabane Raishin of the Unbreakable Machine-Doll series.
Yaya is a lovely high school age girl of Japanese heritage who wears a very short kimono style dress has dark hair that is very shinny , a slender petite figure reddish eyes and a pale complexion. On Yaya's Left side hip , she has a tattoo that identifies her as Yaya of the moon". She is seen in different PJ's and at one point in a nurses outfit tending to Raishin. In some panels of the manga she has a purplish cast to her hair (see photos in gallery on this page)
In the Prologue, Yaya is seen with a sword, which has not been seen since.
Yaya has mostly cordial relations with Charlotte, although is still somewhat more adversarial with Frey due to distress from that her bust is much more petite than Frey's. And she is afraid that may cause Raishin to be attracted to her.
Yaya favors speaking the third-person perspective, both for comic effect and to potentially show her awareness that she is a doll and not a human.
She really loves Raishin, as seen in the First Chapter where she chants words into his ear to love her and marry her and every time a an attractive woman gets close to him she starts to get moody and depressed. She sometimes also gets certain situations wrong. Raishin, on the other hand, cares for Yaya, too. Shown when he saves her from a fatal blow after thinking about another puppet that got killed. Yaya loves Raishin so much and she would go to the ends of Earth for him. Yaya wishes to become human so that she can marry Raishin and have many children with him.