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.

Current Members

 * Otomori Yuu (音森ゆう) (Joined May 18, 2022)
 * Kayano Izumi (茅野伊澄) (Joined June 2022)
 * Saito Rika (齊藤莉歌) (Joined June 2022)
 * Sakura (さくら) (Joined June 2022)
 * Tachibana Kanon (橘花音) (Joined June 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)