Mori Calliope is an English Virtual YouTuber affiliated with hololive’s English (EN) branch, part of the first generation of VTubers. She was introduced on September 8, 2020, through a video posted on hololive’s English YouTube channel and Twitter accounts, alongside other first-generation members.

Her official Twitter account was created in July, but she made her first tweet on September 8. Calliope’s YouTube channel was established on July 16, and she debuted on September 12 with her first original rap song, “失礼しますが、RIP♡” (Excuse My Rudeness, But Could You Please RIP?), which she wrote herself.