Z4-A1

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

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 early March 2022.

Current Members

 * Ide Ryoko (井出涼子) (Joined March 2022)
 * Kujo Arina (空条ありな)
 * Shirasaki Hikari (白咲ひかり)
 * Shirano Koko (白埜ここ) (Joined March 2022)
 * Shirahana Mariya (白花まりや) (Joined March 2022)

Former Members

 * Mito Chinami (美藤千波) (Founding member)
 * Yamada Nao (山田菜緒) (Founding member)
 * Kusunoki Anzu (楠あんず) (Founding member)
 * Harada Yukika (原田ゆきか) (Founding member)
 * Ichiba Uno (市葉羽乃) (Joined March 2022)
 * Kozakura Purple (小桜ぱぷる) (Joined March 2022)