The Pisces Zodiarts is a member of the Horoscopes and a recurring antagonist in the Kamen Rider franchise. While the first Pisces, Ran Kuroki, was not at all evil, in its subsequent appearances the Pisces appeared as antagonistic towards the Kamen Riders.
Kamen Rider Fourze
After discovering that Ran Kuroki was the Pisces Zodiarts, the Horoscopes set up a scenario to trick Ran into using the Switch by staging an attack by the Leo Zodiarts on Kouhei Hayami, causing Ran to become Pisces to save Hayami. However, after she used the switch, it was stolen by Libra and given to Mitsuaki Gamou, allowing the Horoscopes to complete the ritual to open the Hole.
Kamen Rider Fourze the Movie: Everyone, Space is Here!
A dummy replica of the Pisces Switch was created by Gamou along with copies of the other Horoscopes Switches. Gamou intended to sell the switches to Foundation X but the transaction was interrupted by Inga Blink, who stole the switches. Inga later used the Switches to summon the Pisces Zodiarts, along with several other Horoscopes to fight Kamen Riders Fourze and Meteor. However, the Pisces Zodiarts was later destroyed by Kamen Rider Wizard along with the other three remaining Zodiarts.
Kamen Rider x Kamen Rider Gaim & Wizard: Sengoku Battle Royale