Z4-A4

 is a group within Zero Project. The theme of the group is personality.

The first line-up was announced on November 20, 2021.

They made their stage debut on November 21, 2021 @Ebisu Garden Hall.

The second line-up was announced in March 2022.

The third line-up was announced on August 14, 2022.

Current Members

 * Kayano Izumi (茅野伊澄; ) (Originally Joined June 2022, Re-joined November 29, 2022)
 * Saito Madoka (斎藤まどか; ) (Joined November 29, 2022)
 * Shigeta Norika (重田紀果; ) (Originally Joined August 14, 2022, rejoined October 25, 2022)
 * Natsuna Rika (夏菜莉歌; ) (Originally Joined June 2022, Re-joined November 29, 2022)
 * Watanabe Runa (渡辺瑠菜) (Joined November 29, 2022)

Former Members

 * Kururugi Yun (枢木ゆん) (Founding member)
 * Nagase Ryo (永瀬稜) (Founding member)
 * Sorano Hina (昊乃ひな) (Joined March 2022)
 * Aone Konoha (蒼音このは) (Founding member)
 * Aino Momo (愛乃もも) (Joined March 2022)
 * Ameyama Miku (飴山みく) (Joined March 2022)
 * Ikeda Haruki (池田遥希) (Joined March 2022)
 * Uiru (うぃる) (Joined March 2022)
 * Otomori Yuu (音森ゆう) (Joined May 18, 2022)
 * Sakura (さくら) (Joined June 2022)
 * Tachibana Kanon (橘花音) (Joined June 2022)
 * Fuka (颯奏) (Joined July 2022)
 * Aisaka Yuuna (逢坂ゆうな) (Joined August 14, 2022)
 * Kabashima Shinano (樺島信濃) (Joined July 2022)
 * Kiri (きり) (Joined August 14, 2022)
 * Sorane (そらね) (Joined July 2022)
 * Hanamaru Yuzu (円柚羽) (Joined August 14, 2022)
 * Ichigozaki Mayu (一期崎まゆ; ) (Joined September 2022)
 * Takase Miku (高瀬みく; ) (Joined September 2022)
 * Nishina Akari (西奈あかり; ) (Joined September 2022)
 * Hiiragi Aoi (柊あおい; ) (Joined September 2022)
 * Miyamoto Airi (宮本愛莉; ) (Joined September 2022)
 * Aono Kuiru (蒼乃くいる; ) (Joined September 17, 2022)
 * Isshiki Hiyori (一色陽頼; (Joined October 25, 2022)
 * Usami Seina (宇参絢菜; ) (Joined October 25, 2022)
 * Nakajima Motomi (中嶋元美; ) (Joined October 25, 2022)