Kaizensei Altruism

 (蓋然性オルトイズム) is currently a nine-member idol group formed on December 26, 2020 by ONEtoONE Agency and includes former members of TEARS.

They made their stage debut on February 1, 2021 @Shinjuku ReNY.

Current Members

 * Makise Yumi (牧瀬裕美; ) (Original Member)
 * Mizuue Saki (水上咲; ) (Original Member)
 * Kita Conatsu (北こなつ; ) (Joined on March 20, 2021)
 * Hoshina Misaki (星奈実沙希; ) (Joined on November 7, 2021)
 * Hiyori Yuu (日和ゆう; ) (Joined on March 26, 2022)
 * Sakuraba Nana (桜羽なな; ) (Joined on April 24, 2022)
 * Ran Honoka (蘭ほのか; ) (Joined on April 24, 2022)
 * Aoi Nano (葵菜乃; ) (Joined on July 3, 2022)
 * Shirakawa Rena (白川れな; ) (Joined on January 30, 2023)

Former Members

 * Nagatsuki Yuuki (長月優希; ) (Original Member; Withdrew on May 26, 2021)
 * Asahina Nana (朝比奈なな; ) (Original Member; Graduated on June 20, 2021)
 * Shiraishi Neon (白石ねおん; ) (Original Member; Graduated on June 20, 2021)
 * Tachibana Ui (立花憂衣; ) (Original Member; Transferred to Re:INCARNATION on October 4, 2021)
 * Kawashima Arisu (河島有寿; ) (Original Member; Withdrew on March 4, 2022)
 * Aikawa Mana (藍川まな; ) (Joined on July 23, 2021; Transferred to trainee unit on March 16, 2022)
 * Futaba Yui (二葉唯; ) (Joined on July 23, 2021; Transferred to trainee unit on March 16, 2022)
 * Tsuji Kaho (辻海帆; ) (Original Member; Transferred to TEARS on March 19, 2022)
 * Kanzaki Serina (神崎せりな; ) (Joined on March 20, 2021; Inactive since August 2022; Left unknown)
 * Minami Shion (美波紫音; ) (Joined on March 26, 2022; Inactive since August 2022; Left unknown)
 * Kururugi Maho (枢木まほ; ) (Original Member; Graduated on December 31, 2022)

Timeline
Note: 

Singles

 * 1) [2022.06.15] emperor

Digital Singles

 * 1) [2023.08.16] LAST LOVE
 * 2) [2023.08.23] Eien Memories (永遠 Memories)
 * 3) [2023.08.30] Kindan Lover (禁断Lover)
 * 4) [2023.09.06] Kuusou Believe (空想Believe)
 * 5) [2023.09.13] Hana Kotoba ~Kimi wo Wasurenai~ (花言葉〜君を忘れない〜)
 * 6) [2023.09.20] Hoshigarina Boku ni Kiss wo Shite (欲しがりな僕に kiss をして)
 * 7) [2023.09.27] Namida no Ryou Omoi (ナミダの両思い)