Z4-D1

 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 March 2022.

Current Members
None currently

Former Members

 * Ichiba Uno (市葉羽乃) (Founding member)
 * Mori-chan (もりちゃん) (Founding member)
 * Luna (月) (Founding member)
 * Kurumisawa Narumi (胡桃沢成未) (Founding member)
 * Wakamiya Yuriko (若宮ゆりこ) (Joined March 2022)
 * Watarai Urumi (綿来うるみ) (Joined March 2022)
 * Aono Kuiru (蒼乃くいる) (Joined May 2022)
 * Himesaki Azumi (姫咲あずみ) (Joined March 2022)
 * Momoa Mahiro (桃愛まひろ) (Joined March 2022)
 * Yayoi Megu (弥生めぐ) (Joined March 2022)