Wakana Sonozaki is a member of the Sonozaki Family who is a popular idol in Futo City and a major antagonist in Kamen Rider W.
The middle child of the Sonozaki Family, Wakana was secretly raised by Ryubee Sonozaki to be a key component in his plans for the Gaia Impact after the death of her brother Raito Sonozaki. Unlike the rest of the Sonozaki Family, Wakana had little involvement with the Gaia Memory distribution, instead working as a DJ at Futo's local Wind Wave radio station, where she hosted the popular Wakana's Healing Princess show.
Wakana ilater met Philip and took a liking to him. However, this causes her to begin having second thoughts about being a Dopant, leading to her discarding the ClayDoll Memory and telling her father that she lost it. However, Ryubee did not fall for Wakana's lie and returned to her. After Kirihiko Sudo's death Wakana becomes more involved with the family business. She becomes an unwilling guinea pig of Dr. Shinkuro Isaka after he modifies her Gaia Driver at her sister Saeko's request to allow her to be controlled by the Puppeteer Dopant. Under the Puppeteer Dopant's control, the ClayDoll Dopant attacks the Narumi Detective Agency and nearly kills Philip. To make Wakana to reach her full potential as the ClayDoll Dopant, Isaka begins exposing her to more of her Gaia Memory's influence, making it more dangerous for her to use.
Wakana tries to run away with Philip, but her father stops her and takes her to the Museum's true base of operations to reveal to her Museum's true plans. Wakana is also appointed the new head of the Digal Corporation following Saeko's betrayal and becomes set on bringing Philip back to the Museum by any means so he can fulfill his part in the Gaia Impact. Ryubee also gives her the Prototype Organic Information Controlling Organ Body Gaia Progressor to evolve her into the extremely powerful ClayDoll Xtreme and prepare her for the Gaia Impact so she can become one with the planet's vast knowledge. After Philip is thrown into the source of the true Gaia Memory, the Gaia Impact seems to succeed, only for Philip to be removed from her body, causing an explosion that engulfs the Sonozaki estate. As the estate burns to the ground, an unconscious Wakana is taken by Jun Kazu to the Foundation X research facility.
At the facility, Kazu plots to convert Wakana into data so he can reactivate her Memory and place her in one of the Foundation's satellites to re-instigate the Gaia Impact and broadcast it on a planet-wide scale. Saeko shows up to rescue Wakana and transforms into the Taboo Dopant to hold off Kazu as the Utopia Dopant to give her time to escape, leading to her demise in an attempt to buy Wakana time. Kazu then captures Wakana again and hooks her up to a machine to convert her into data, only for Shotaro Hidari to then arrive and rescue Wakana as well as kill Kazu.
After Kazu's death, Wakana was then taken to a hospital where she resided for a few days. Wakana attempts leave and go continue her family's goal but stops when she learns that Philip disappeared into the Gaia Memory. After getting the means to invoke the Gaia Impact from Shroud in her final moments, Wakana sacrifices herself to bring her brother back via the Xtreme Memory. As she fades, Wakana gives a tearful goodbye to Philip before joining the rest of their family in the afterlife.