|This article is about a rider in Kamen Rider Fourze.|
Tsubasa (ツバサ, Tsubasa) is Kamen Rider Ikaros (仮面ライダーイカロス, Kamen Raidā Ikarosu) and the main antagonist of Kamen Rider Fourze: ~Ama High Graduation~. A fragment of the SOLU organism split off from Nadeshiko Misaki that copied the appearance of Sarina Sonoda and took on voice of her late childhood friend, Tsubasa Amano. The fragment was attached to Virgo during Fourze and Nadeshiko's battle against him during Movie War Mega Max.
During the battle between Kamen Rider Fourze and Nadeshiko against Virgo, a piece of SOLU from Nadeshiko was attached to him. Upon returning to the M-BUS, the SOLU fragment explored the stationed and found the bodies of Sarina Sonoda, Natsuji Kijima, and Yuta Sugiura, who were sealed in suspended animation.
Upon absorbing the intelligence from each of them and the M-BUS' equipment, the SOLU fragment took on Sarina Sonoda's form and wore a bloody Amanogawa High uniform and her face was covered in messy bangs. The fragment that took on Sarina Sonoda's appearance had a male voice, which was modeled after her late childhood friend, Tsubasa Amano (天野ツバサ, Amano Tsubasa), therefore the SOLU fragment referred itself as "Tsubasa".
The personality that the SOLU had mimicked was a repressed split personality that lingered Sarina Sonoda's mind. In the past, Sonoda had an argument with Tsubasa and stormed off. When Tsubasa tried to follow her, he was involved in an accident and was died right in front of her. Upon seeing this, Sonoda continued to blame himself, and unconsciously formed a darker personality that continued to affect her as an adult during her activites as Scorpio due to her regret and anger. It was due to this that a new personality was born from the darkness of Sonoda's heart and the form that the SOLU fragment took was based on the day during Tsubasa Amano's death.
After the deaths of Kuniteru Emoto and Mitsuaki Gamou, after Fourze Cosmic States transported the M-BUS captives back to Earth, "Tsubasa" followed them. It was able to create a Rider System based on the "memory of the Kamen Riders" which combined the Fourze Driver & Meteor Driver, using it to transform into Kamen Rider Ikaros. "Ikaros" was named after the I.K.A.R.O.S. rocket that Sonoda dreamed to ride.
Ikaros was responisble for creating the Pyxis Zodiarts, Carina Zodiarts, Puppis Zodiarts and Vela Zodiarts by giving the Switches to problem children who were stressed during the upcoming events of Amanogawa High School prom. It sought to obtain a large amount of strong energy from despair and fear. It was able to create the Argo Zodiarts after fusing the four Zodiarts into one.
Upon absorbing the dreams of the real Sarina Sonoda and Yuki Jojima, Ikaros took on the form of Beast Ikaros (獣イカロス, Kemono Ikarosu). Although Beast Ikaros overwhelmed Fourze, he brought the creature to space after transforming into Cosmic States. Although it was beginning to fall back into its non-sentient state, Ikaros did not want to lose to Fourze. However, it was defeated by Fourze Launcher States' Limit Break and reverted back to its SOLU form. Before returning back to space, Ikaros expressed to Gentaro his hopes of becoming friends the next time they encounter each other.