This article is also available in Japanese: Read the Japanese version
“WAZZUP!! It's your worldwide Rat Idol --- Hakos Baelz!”
That's the catchphrase on Hakos Baelz's talent page on the official hololive website. Baelz is a member of hololive English -Promise-. In Japanese, her name is written ハコス・ベールズ. Her YouTube channel had 1.22 million subscribers when we checked on September 26, 2026. Her birthday is February 29, so her real birthday comes around only once every four years.
In this article, we'll first look at her official profile, her debut day, and her February 28 “not-birthday stream.” After that, we'll go through the songs she wrote lyrics for, one by one, all the way up to her 1st Concert in December.
When Is Hakos Baelz's Birthday, and How Tall Is She?
Birthday: February 29
Debut Stream: August 23, 2021
Height: 149 cm
Unit: hololive -Promise-
Illustrator: Mika Pikazo
Her fan name is “Brats.” All of this comes from the “DATA” section of her talent page on the official hololive website (checked September 26, 2026, on the Japanese page, and October 29, 2026, on the English page linked here).
Her Likes run from coffee and fried cheese to RPGs and anisong, all the way to hardstyle. Her Dislikes: “The dark, jump scares.”
Her official profile describes her this way: “Chaos. Mayhem. Entropy..... All in the form of a cute little rat.” It also says: “Occassionally she will get swept up in her own storm, but thats just part of the fun.” So it seems she's set up as a bundle of chaos that even she can't keep under control.
Her YouTube channel description opens with the English self-introduction “just a lil rat idol who wants to make you smile!” Right below it is a line in Japanese: “ネズミアイドルでちゅ～！よろしくでちゅ～！” (roughly, “I'm a rat idol! Nice to meet you!” in baby talk).
Her Debut: The Morning of August 23, 2021
Baelz's debut stream was titled “《DEBUT STREAM》- LET'S GET THIS PARTY STARTED!” It started at 8:00 a.m. JST on August 23, 2021, the same date the official data gives for her debut stream. The first line of the description was “It's party time ~ 遊びの時間だぜ” (“it's playtime”), with English and Japanese side by side.
The description also lists the four others debuting that same day, along with their debut times. They are “Tsukumo Sana,” “Ceres Fauna,” “Ouro Kronii,” and “Nanashi Mumei.” Their slots ran from 2:00 a.m. to 6:30 a.m. JST, and a “First Group Collab” was also scheduled for 10:00 a.m. that same day.
The debut stream's title carried the hashtag “#holoCouncil,” while the unit name in her current official data is “-Promise-.” In the primary sources we checked, we couldn't find when or how the name changed.
Incidentally, the fan-name field in that description still read “？？？”. Just two days later, the description of her August 25, 2021, stream already included “#baerats (brats).” It seems the fan name was settled soon after her debut.
A Birthday That Comes Only Once Every Four Years
Because she was born on February 29, her birthday isn't on the calendar in non-leap years. On February 28, 2022, she held a stream titled “≪#ItsNotBaesBday≫ NOT-BIRTHDAY STREAM.” The first line of its description was “BUT WE STILL PARTYING!!!” The next year, on February 28, 2023, she streamed again with the hashtag “#StillNotBaeBday,” under the title “Birthday Stream fr fr [NOT CLICKBAIT].” Turning “it's not my birthday, but we're celebrating anyway” into a game, right down to the hashtag, is very much Baelz.
Then, in the leap year 2024, she streamed “DREAMCATCHER 3D LIVE” on her actual birthday, February 29. The stream's credits ended with “DIRECTION Hakos Baelz.” Nine guests were listed, including Natsuiro Matsuri and Tokoyami Towa, with Yuki Aoi (Aoni Production) credited as a special guest. The MV for her original song “R x R x R” was released the same day, and sales of her 1st album, ZODIAC, had begun as well.
In both 2025 and 2026, she streamed a 3D birthday live on February 28; the 2026 one was titled “ReCOLOR 3D LIVE.”
Her First Original, “PLAY DICE!” — and “PSYCHO”
Baelz's first original song is “PLAY DICE!” Its MV came out on February 28, 2022, the same day as the “not-birthday stream” mentioned above. That day's stream description also says “FIRST ORIGINAL「PLAY DICE!」.” According to the MV's description, the composition is by Camellia, and the lyrics are credited to “Camellia & Hakos Baelz.”
As of September 26, 2026, “PLAY DICE!” had more than 12 million views. That made it the most-viewed video on her channel. Second was “PSYCHO,” whose MV came out on May 5, 2023; as of September 26, 2026, it had passed 10.5 million views. “PSYCHO” has lyrics by ZAQ and music by タカハシヒビキ and Tom-H@ck, with Baelz on vocals.
Her 1st album, ZODIAC (2024), has 13 tracks. In the album trailer's description, Baelz's name appears in the lyrics credits for three tracks: “The Fight Song,” “RIDE,” and “GIMME MORE.”
“SNAKE EYES”: Her Name in the Lyrics and Choreography Credits
On February 28, 2026, the same day as her 3D birthday live, the 3D MV for “SNAKE EYES” was released. Its description reads “Lyrics: Hakos Baelz, WON AGAIN” and also “Choreography: Hakos Baelz.” That would mean she co-wrote the lyrics with WON AGAIN and did the choreography herself.
As of September 26, 2026, this MV had more than 10.3 million views. Roughly seven months after its release, it seems to be closing in on “PSYCHO.” On April 20, 2026, a “3D Performance Video” of the same song was also released.
2nd Album Mirror Mirror and “I found me”
On August 23, 2026, COVER Corporation announced her 2nd album in a press release on PR TIMES (in Japanese). The album is titled Mirror Mirror, and as of that announcement, shipping and digital distribution were scheduled to begin on November 2, 2026. According to COVER's announcement, in addition to the pre-release single “SNAKE EYES,” the album “features numerous tracks with lyrics penned by Hakos Baelz herself.” Its theme is “reflection = facing oneself,” and the lineup was eight songs, including “SNAKE EYES” and “I found me,” plus a bonus track.
Also on August 23, the animated MV for her new song “I found me” was released. Its credit line reads “Vocal & Lyrics: Hakos Baelz.” Baelz wrote the lyrics on her own. The release, too, introduced the album's “core track” as “a song she poured herself into, with lyrics she wrote herself” (translated from COVER's Japanese press release).
The release describes the song as “a story of rebirth: joining hands with ‘the other me’ in the mirror and reclaiming her true self.” It sounds like the song ties into the album's title, Mirror Mirror.
1st Concert “REGALIA” at Kanadevia Hall
The same release also announced that Hakos Baelz 1st Concert “REGALIA” would be held on Tuesday, December 1, 2026. The venue is Kanadevia Hall in Koraku, Bunkyo-ku, Tokyo. As of the release on August 23, details were “to be announced later,” and the official hashtag was “#Baelz1stConcert.”
That said, Baelz has streamed a 3D birthday live every year from 2024 through 2026. So instead of calling it her “first solo concert,” we'll stick to describing it as a show billed as her “1st Concert.”
A Game Starring Baelz, and a Nendoroid
On August 28, 2026, CCMC Corp., a wholly owned subsidiary of COVER Corporation, issued a press release about a game on PR TIMES (in Japanese). It announced that the Steam store page was up for BaeSplit: Chaos Down Under, a title from holo Indie, hololive production's brand for fan-made games.
According to the release, Baelz and her friends are traveling around Australia when “the power of chaos runs amok” (translated from CCMC's Japanese press release). The story follows her across all of Australia to rescue her scattered companions. It's a turn-based RPG in which you fight by combining “six versions of Hakos Baelz,” and the price was listed as “free.” It seems the “chaos” premise from her official profile has become the game's story just as it is.
At the time of the release, the release date was “TBD.” When we checked the Steam store page on September 26, 2026, the release date field read “2027.”
Also, on June 29, 2026, the company that runs the hobby retailer AmiAmi (大網株式会社) announced a Nendoroid of her in a press release on PR TIMES (in Japanese). Its optional parts include “Mr. Squeaks” and “cheese” (translated from the Japanese press release). As of that release, it was “scheduled for January 2027.” Her channel also has a stream from August 22, 2022, titled “MR SQUEAKS DEBUT,” so Mr. Squeaks is probably a character who appears alongside her.
Beyond that, she was chosen as one of five 2024 ambassadors for “hololive Meet,” alongside Kobo Kanaeru and others.
Wrapping Up
As we've seen, Hakos Baelz is a member of hololive English -Promise- whose character is built on “chaos.” She has the playful streak to turn a birthday that comes only once every four years into a “not-birthday stream” hashtag. At the same time, her name appeared under DIRECTION in the credits of her 3D live. She has helped write lyrics since her first song, “PLAY DICE!,” and in 2026 she wrote the lyrics to “I found me” entirely on her own. With the album slated for November 2026 and “REGALIA” set for December 1, we can't wait to hear what songs she has in store.
