Mori Calliope Profile: Reaper's Apprentice, Gachiakuta OP & LA Concert
This article is also available in Japanese: Read the Japanese version
“Dead Beats, listen up! Your Mori's been working hard for you!”
That's the line the hololive official website uses to introduce Mori Calliope on her talent page. She's a member of -Myth-, part of hololive English, the branch aimed at English-speaking audiences. In Japanese, her name is written 森カリオペ. As of September 25, 2026, her YouTube channel had 2.65 million subscribers, by our own count.
In this profile, we'll walk through her official data and character backstory, her very first stream and original songs, and then the tie-in songs and concerts that followed her major-label debut.
When Is Mori Calliope's Birthday, and How Tall Is She? Her Official Data
Birthday: April 4
Debut Stream: September 12, 2020
Height: 167 cm
Unit: hololive -Myth-
Illustrator: Yukisame
Fan Name: Dead Beats
These details come from the “DATA” section of her talent page on the hololive official website (checked October 24, 2026). The same section lists her stream tags as #calliolive and #カリオライブ, and her fan-art tags as #callillust and #カリイラスト. Offering both English and Japanese tags is probably a way to reach her Japanese fans, too.
She has held a birthday stream on April 4 pretty much every year. On April 4, 2026, that meant a 3D live show titled “Mori Calliope 6th Birthday (feat. LIVE BAND).” For fans, it's likely become a fixture of every April.
The official data doesn't include a birth year, so we don't calculate or state her age.
“The Grim Reaper's First Apprentice”: Her Character Backstory
The bio on the official talent page opens with a single line: “The Grim Reaper's first apprentice.” It goes on: “Due to modern medical care causing a decline in the reaping business, Calliope decided to become a VTuber to harvest souls instead.”
A story that kicks off with medical progress putting the reaper out of work? That's a pretty clever twist.
And it closes with: “That being said, despite the image her hardcore vocals and manner of speech gives off, she's actually a gentle-hearted girl who cares greatly for her friends.” This is official character copy written for the persona. The gap between that scary title and the gentle, caring friend underneath may well be the best part of the whole bio.
The description on her own YouTube channel opens with a short self-introduction: “singer/songwriter. Death Herself. 作曲作詞.” (the last part is Japanese for “composing and lyric writing”). Here, being Death and being someone who writes and sings her own songs seem to carry equal weight.
The Debut Stream That Led Off Myth
Mori Calliope's debut stream went live at 8:01 p.m. JST on September 12, 2020, the same date listed as her official debut. It was titled “【DEBUT STREAM】Memento Mori! What is Up, Humans?!” and ran for about an hour.
The stream's description also lays out the schedule for the other Myth members debuting around the same time. It lists Takanashi Kiara from 10 p.m. on September 12, Ninomae Ina'nis from 4 a.m. on September 13, Gawr Gura from 6 a.m., and Watson Amelia from 8 a.m. (all JST). Since her stream started before all four of theirs, she was effectively the first of Myth's five members to go live.
The Japanese part of the description includes the line “日本語でも頑張る、あたしね～” (“I'll do my best in Japanese too, y'know!” — translated from the Japanese). She belongs to a group aimed at English-speaking audiences, but she seems to have had Japanese viewers in mind from day one.
Embedding is disabled for this debut stream, so we're only mentioning it by title here.
Her Most-Watched Video: First Original Song “失礼しますが、RIP♡”
In the early hours of September 13, 2020 (JST), the day after her debut stream, Mori Calliope released her first original song. It's titled “失礼しますが、RIP♡,” with the English subtitle “Excuse My Rudeness, But Could You Please RIP?”
As of September 25, 2026, the video had about 44.06 million views, the most of any public video still on her channel. Its description calls it “My first original song” and explains that it's from her debut EP, DEAD BEATS.
On September 15, she followed it with a rap called “DEAD BEATS,” sharing its name with her fan name. As of September 25, 2026, that one had about 18.79 million views. Putting out her own raps back-to-back within days of her debut, she arguably started out exactly as her “singer/songwriter” label promised.
The second most-watched video on the channel is “Q,” released on February 4, 2022. It credits Gawr Gura (also named in that debut schedule) and DECO*27 alongside her, and had about 33.10 million views as of September 25, 2026.
Major-Label Debut and Tie-In Songs
COVER Corporation's March 25, 2026 press release describes Mori Calliope as having “gained popularity with rap and music production mixing English and Japanese” (translated from the Japanese press release). The same release states that she “made her major debut with Universal Music in 2022 and reached No. 1 on music charts in Japan and the US.” Her channel also still has a video from April 6, 2022, whose title opens with “[Universal Music Debut].”
Her later songs stand out for their tie-ins with anime and manga. Going by what the video titles and descriptions say, here's the list:
- July 2023: “未来島 ~Future Island~” (official theme song for Volume 106 of ONE PIECE)
- September 2024: “Go-Getters” (ending theme of Suicide Squad Isekai)
- November 2025: “LET'S JUST CRASH” (the second opening theme of the TV anime Gachiakuta)
The MV for “LET'S JUST CRASH” had about 10.55 million views as of September 25, 2026. According to its description, her third major-label album, DISASTERPIECE, released February 6, 2026, includes several other tie-in songs besides this one. Among them are “Gold Unbalance feat. Kento Nakajima,” the theme song of Prime Video's comedy competition THE GOLDEN COMBI 2025, and “Die For You,” her contribution to the original soundtrack of TV Asahi's Friday Night Drama Mamono.
A VTuber's songs turning up in a network TV drama and a streaming show says a lot about how far her work has spread.
Most recently, the MV for “黎明Compass” was released on September 13, 2026. Its description lists Mori Calliope herself in the lyrics credit.
From Toyosu PIT to Los Angeles to Apple Omotesando
The stages she performs on have been steadily widening, too. According to COVER Corporation's November 23, 2024 press release, her first solo concert was “New Underworld Order,” held at Toyosu PIT (Tokyo) in July 2022.
The same release announced that her second solo concert, “Grimoire,” would be held at the Hollywood Palladium in Los Angeles on February 27, 2025 (JST), the evening of February 26 local time. The release says it would be “the first solo concert by a hololive production talent held outside Japan” (translated from the Japanese press release). For a Myth member who works in English, it feels like a fitting choice of stage.
Then the March 25, 2026 press release announced that she would appear at an event in Tokyo celebrating Apple's 50th anniversary. The release gave the venue as Apple Omotesando, and the date and time as March 27, 2026, from 7:00 p.m. JST. That release also includes this comment from Mori Calliope herself:
“The first Apple product I ever owned was a bright red iPod nano. The time I spent with it, loaded up with the anime songs I loved, made me who I am today.” (translated from the Japanese press release)
Her words about anime songs making her who she is seem to echo where she is now, singing tie-in songs for anime herself.
Later, on April 5, 2026, a Short with “Congratulations Apple 50th!” in its title went up on her channel.
How Big Is Her YouTube Channel? Subscribers and Upload History
The figures for her YouTube channel, “Mori Calliope Ch. hololive,” are our own measurements, taken on September 25, 2026. On that date, the channel had 2.65 million subscribers. It was created on July 16, 2020.
Here's how many public videos remain on the channel, counted by the year they were published (as of September 25, 2026):
2020 (from September): 98 videos
2021: 288 videos
2022: 220 videos
2023: 289 videos
2024: 381 videos
2025: 276 videos
In each of the six years from her 2020 debut through 2025, roughly 100 or more videos remain on the channel. Most of them are live stream archives. Even as her music career has grown, the channel still seems to be built around streaming.
Uploads have continued into 2026: when we checked on September 25, 2026, her most recent new video had gone up on September 22. On September 13, 2026, she also held an anniversary stream titled “【6th Anniversary Event】DEATH Before DISCO!!” The uploads look set to keep coming.
Has Mori Calliope's Real Name or Age Been Made Public?
Mori Calliope's real name and age did not appear in any of the sources we checked: the official talent page, her channel and video descriptions, and the two COVER Corporation press releases. So the most we can say is that, as far as we've checked, they have not been made public.
When writing about VTubers, the character's profile and the personal information of the person who performs the character need to be kept separate. This site does not speculate about anything she has not made public herself. What we present here is officially published data, such as her April 4 birthday and her height of 167 cm.
Summary
As we've seen, Mori Calliope is a VTuber who debuted on September 12, 2020, as a member of hololive English -Myth-. “失礼しますが、RIP♡,” the original song she released the day after her debut, became the most-watched video on her channel, and she has since sung tie-in songs for ONE PIECE and Gachiakuta. As of September 25, 2026, she had 2.65 million subscribers.
What songs will “The Grim Reaper's first apprentice” sing next, and on what stages? We can't wait to find out.
