Not sure what the copyright for this vtuber should be, since it seems she's no longer active. Both her Twitter and Youtube have been deleted, and the only information I can find on her in English is from this Reddit post, which says she was part of some sort of Hiroshima promotional vtuber group. The Showroom channel linked in the post is dead too
EDIT: Turns out one of the three girls in this group is still active. Used her YouTube bio to find the Japanese name for the trio, so the copyright tag is Virtual Kouhou Taishi Project