SIRIUS

 was an idol group active from August 2018 to April 2019. In November 2018, five members of the group split off to form MERCURY.

Final Line-up

 * Arai Shiina (新井椎夏)
 * Hayashi Honoka (林甫希珂)
 * Terao Nene (寺尾音々)
 * Saya (さや)

Former Members

 * Kiara Mai (きあらまい) (Transferred to MERCURY November 2018)
 * Mizuno Yua (水野由彩) (Transferred to MERCURY November 2018)
 * Minami Nami (みなみなみ) (Transferred to MERCURY November 2018)
 * Muto Haruka (むとうはるか) (Transferred to MERCURY November 2018)
 * Ayano Momoe (綾野百恵) (Transferred to MERCURY November 2018)