Between November 2017 and January 2018, they released the solo single albums for new members Yves, Chuu, and Go Won, continuing the monthly pattern along with the digital single "The Carol 2.0" sung by Yves, Vivi, and Choerry. In March 2018, they released the solo single album for final member, Chandler Hye. On May 30, 2018, the group's third sub-unit, Loona yyxy, made their debut with the extended play "Beauty & the Beat". The single "love4eva" featuring Canadian musician Grimes was released the same day with a music video. The extended play reached number 4 on the Gaon Album Chart.