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.

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

Current Members

 * Akaishi Rena (赤石玲菜) (Joined July 2023)
 * Sakura Aya (桜あや) (Joined July 2023)
 * Hoshiai Rine (星合里音) (Joined July 2023)
 * Yagumo Ritsu (星合里音) (Joined July 2023)
 * RINO (Joined July 2023)

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)
 * Ide Ryoko (井出涼子) (Joined March 2022)
 * Shirahana Mariya (白花まりや) (Joined March 2022)
 * Usami Momo (うさみもも) (Joined May 2022)
 * Kujo Arina (空条ありな) (Joined April 2022)
 * Shirasaki Hikari (白咲ひかり) Joined April 2022)
 * Nekoyashiki Aoi (猫夜色あおい) (Joined May 2022)
 * Aino Momo (愛乃もも) (Joined June 2022)
 * Shirano Koko (白埜ここ) (Joined March 2022)
 * Yayoi Megu (弥生めぐ) (Joined June 2022)
 * Momoa Mahiro (桃愛まひろ) (Joined June 2022)
 * Yoshida Momo (吉田桃) (Joined July 2022)
 * Aono Kuiru (蒼乃くいる) (Joined June 2022)
 * Anon (あのん) (Joined June 2022)
 * Saito Rika (齊藤莉歌) (Joined August 14, 2022)
 * Sekai Kaju (世界かじゅ) (Joined July 2022)
 * Hanamiya Ayaka (花宮あやか) (Joined August 14, 2022)
 * Hoshino Himari (星乃ひまり) (Joined July 2022)
 * Inoue Tsumugi (井上紬葵; ) (Joined September 2022)
 * Umesaki Risa (梅咲りさ; ) (Joined September 2022)
 * Sakuraba Kaho (桜葉かほ; ) (Joined September 2022)
 * Hirata Mitsuki (平田みつき; ) (Joined September 2022)
 * Misaki Momoka (三崎桃果; ) (Joined September 2022)
 * Aito Sakura (愛桃さくら; ) (Joined October 25, 2022)
 * Amatsuka Mio (天使みお; (Joined October 25, 2022)
 * Onishi Meria (尾西苺梨愛; ) (Joined October 25, 2022)
 * Miura Juri (三浦樹里; ) (Joined October 25, 2022)
 * Yuyu (ゆゆ; ) (Joined September 17, 2022)
 * Nono (ﾉﾉ; ) (Joined November 29, 2022)
 * Hanamaru Yuzu (花円柚羽; ) (Joined November 29, 2022)
 * Mashiro Momo (真城もも) (Joined November 29, 2022)
 * Aimi Yuka (藍南ゆか) (Joined November 29, 2022)
 * Chida Kanon (千田果穏) (Joined December 28, 2022)
 * Tsukimi Seri (月見セリ) (Joined December 28, 2022)
 * Kae (カエ) (Joined December 28, 2022)
 * Hirose Asuka (広瀬飛鳥; ) (Joined December 28, 2022)
 * Ayase Mayo (絢瀬まよ; ) (Joined November 29, 2022, Re-Joined March 6, 2023)
 * Isshiki Hiyori (一色陽頼) (Joined March 6, 2023)
 * Hanamaru Yuzu (花円柚羽) (Joined March 6, 2023)
 * Hamabe Mizuka (浜辺美珠香; ) (Joined December 28, 2022)
 * Yoi (宵) (Joined March 6, 2023)
 * Okada Reiko (岡田怜子) (Joined May 24, 2023)
 * Hikari (ひかり) (Joined May 24, 2023)
 * Rukino (るきの) (Joined May 24, 2023)