Rib's upcoming 5th album, Ratimeria, set for release after five and a half years, will feature a special collaboration with Ado. The two artists will perform "Matryoshka," a song originally produced in 2010 by Kenshi Yonezu under his Vocaloid producer alias, Hachi. This collaboration will be included in the "Collaboration Singing Collection" CD, available with the album’s limited edition.

Ado has previously expressed admiration for Rib as a vocalist, while Rib has also hoped to collaborate with Ado. Their long-awaited duet brings together one of the most influential vocalists of the Reiwa era and a key figure from the early days of the Japanese online music scene.

The album will include eight tracks, featuring contributions from top creators such as Eve, who composed "Twilight," the ending theme for the anime Tasokare Hotel, and Kenmochi Hidefumi, who wrote the lyrics for "Play," the theme song for the drama Shachiku Jin Yabuu, with composition and arrangement by Giga. The limited edition will also include collaborations with other vocalists, such as "Fireঌfly" with Chogakusei and "Yamitai Girl" with Senra.

Additionally, a special serial code for priority ticket reservations will be included in the first edition of the album. This will grant fans early access to Rib 15th Anniversary Live “Into the Abyss”, scheduled for September 6 and 7, 2025, at Yokohama BUNTAI. This marks Rib’s first solo live performance in approximately five and a half years.

Ratimeria will be released on May 14, 2025.