VIVIZ is a four-person team, consisting of Irene and Yeri, members of Korean women's group Red Velvet, and Min Kim Xi and Zhisheng Piao, members of aespa.

There may be many reasons why other members don't join VIVIZ, such as personal development planning, team style mismatch and so on. In addition, both Red Velvet and Espa have their own musical styles and orientations, and each member also has his own field of expertise, which is not necessarily suitable for forming a lyric team like VIVIZ.

Therefore, although no other members of Red Velvet and Espa have joined VIVIZ, it does not mean that other members do not want to join, but it has not been realized for various reasons.