Soon after, Eguchi receives a Zodiarts Switch from the Libra Zodiarts which causes him to develop a split personality with the dark aspects of himself occupying the Cygnus Zodiarts, which simply calls himself "Cygnus". As the Cygnus Zodiarts, he is armed with sharp claws on his hands, and he uses his feathers for multiple purposes from throwing them around to make a grand entrance to using them as shurikens, and has powerful kicks that resemble ballet moves.
Portraying himself as a hero, the Cygnus Zodiarts obtains a large following of people called the Ugly Duckling Society, which is led by Misa Toriizaki, who uses a point system to judge people like the Zodiarts does. While claiming to be a hero of justice, Cygnus actually wants admiration and will attack anyone who he sees as a threat to his true plan: replacing Kamen Rider Fourze, as well as those who refuse to see him as a superior being.
When Eguchi is revealed to be the Switcher, having no knowledge that Cygnus was the product of his own mind, he attempts to give his Zodiarts Switch to the Kamen Rider Club as the item assumes its Last One state. However, the Cancer Zodiarts abducts him so Misa can force Eguchi to transform before the Cygnus Zodiarts reveals his true colors. After the Cygnus Zodiarts is destroyed by Kamen Rider Meteor, Eguchi lives his dream of being a hero with good deeds.