Because of her intense need to discover the truth behind events, she discovers the identities of three former Zodiarts Switchers prior to receiving a Zodiarts Switch from Cancer. As the Coma Zodiarts, she is able to use her hair as tendrils to whip at people or to create clones of defeated Zodiarts and control them like puppets by pulling a strand off.
It should be noted that while her clones have the same powers as the real articles, what separates them is that they do not possess the same specific material make-up as the original ones, as demonstrated when the Puppet Version of the Dragon Zodiarts cannot be magnetized due to the non-metallic nature of real hair.
The Coma Zodiarts had created clones of the Chameleon, Altar, Dragon Zodiarts to run amok in the school all for a scoop, not caring if the former Switchers get their names sullied by the incriminating false evidence.She was hit by Meteor's Starlight Shower when she made the mistake of wrapping the Rider in her tendril-like hair and pulled him close. However, as she wasn't in Last One yet, Yayoi still had the Switch in hand, then reassumed Zodiarts form and fled.
The real reason why she became a Zodiarts is because she doesn't want to graduate and leave Amanogawa High School, and decided to use her Zodiarts Switch to cancel Prom Night. However, that clashed with Gentaro's present to the third-year students, which is the Prom Night event itself. After Coma assumes Last One and a fierce battle involving the Cancer Zodiarts butting in again, the PowerDizer's pilot JK getting ejected, and the eldest Club members returning to the fold, Fourze assumes Magnet States and pulls off the Rider Super Electromagnetic Tackle when Shun in the PowerDizer grabbed the two Zodiarts and drove to Gentaro. While the Cancer Zodiarts managed to get away, Yayoi wasn't so lucky and was returned to normal.