Yui Mizuno was born on June 20, 1999, in Kanagawa Prefecture, Japan.
Her entertainment career began several years before Sakura Gakuin and BABYMETAL.
In 2007, she worked as a child reader model and subsequently entered the Amuse child-entertainment environment.
Her confirmed early credits include a 2008 television commercial for Bandai's Pretty Cure innerwear line.
In 2009, she appeared in the Fuji TV 50th-anniversary special drama Happy Birthday.
In May 2010, she appeared in the stage production Okuribito.
Historical profiles also connect her with other television work from this child-performer period, but the Bandai commercial, Happy Birthday and Okuribito are the clearest credits preserved in Japanese entertainment databases.
These early projects are significant because Yui did not enter Sakura Gakuin without previous professional experience.
Before becoming known primarily as a dancer and singer, she had already worked in: modeling, commercial advertising, television drama, and theater.
One of the most important musical influences in Yui's childhood was Karen Girl's.
Karen Girl's was a three-member group formed around songs for the anime Zettai Karen Children.
Its members included: Ayami Muto, Yuika Shima, and Suzuka Nakamoto.
Yui later explained that Karen Girl's music had given her emotional support during a difficult period in which a member of her family faced a serious medical situation.
She became a devoted fan and attended the group's farewell event after its short activity period ended.
Karen Girl's therefore connected several parts of Yui's later story before she could have known how closely those parts would converge.
Ayami Muto and Suzuka Nakamoto would become senior members of Sakura Gakuin.
Suzuka would also become SU-METAL, the lead vocalist beside Yui in BABYMETAL.
In August 2010, Yui joined Sakura Gakuin together with Moa Kikuchi.
The two were introduced as the group's first transfer students rather than part of the original founding lineup.
Both were fifth-grade elementary-school students and quickly became closely associated as the group's youngest pair.
During the Sakura Gakuin entrance-test period, Yui and Moa performed Karen Girl's “Over the Future,” giving Yui the unusual experience of presenting a song by the group she had admired within a project that included former Karen Girl's members.
Sakura Gakuin was built around the concept of a fictional school.
It was explicitly a “growth-period limited” group: members could remain only until completing junior high school, after which they were required to graduate.
The main group was accompanied by smaller club units, annual school-year albums, student-council roles, public lessons and written “school diary” entries.
For Yui, this structure became the center of her adolescence and the foundation for her later international career.
Her first major club unit was the Baton Club: Twinklestars.
Twinklestars combined idol performance with synchronized baton choreography.
Its repertoire included: “Dear Mr. Socrates,” “Please! Please! Please!,” “Rapikamu,” and “Tenshi to Akuma.”
The technical demands of baton work reinforced the precision that later became central to Yui's public identity as a dancer.
In 2011, Yui also became part of the second-generation Cooking Club: Mini-Pati.
The original lineup of Nene Sugisaki, Raura Iida and Marina Horiuchi handed the unit to: Yui Mizuno, Moa Kikuchi, and Hana Taguchi.
The trio remained active through the 2014 school year.
Mini-Pati songs included: “Happy Birthday,” “Princess☆a la mode,” “Yokubari Fille,” “Miracle♪Patiful♪Hamburger,” “Acha! Cha! Curry,” “Shanari Hannari Dorayaki Hime,” “Hirari! Kirakira☆Yamiyami Museum,” “Jakapara Goo Goo♡Omelette Rice,” and “Dabada♪Salad de Sebon☆Avenue.”
Yui and Moa also appeared together as “chart girls” on TV Kanagawa's saku saku.
From May 2011 through March 2013, they presented the program's weekly Kanagawa CD-single sales-ranking segment.
This gave the pair recurring television experience outside the normal Sakura Gakuin concert framework.
At the same time, Yui entered the club unit that would eventually become much larger than Sakura Gakuin itself.
In 2010, Suzuka Nakamoto, Yui Mizuno and Moa Kikuchi were selected for Sakura Gakuin's Heavy Music Club.
They became: SU-METAL, YUIMETAL, and MOAMETAL.
The unit was named BABYMETAL.
The original concept combined: heavy-metal instrumentation, melodic lead singing, supporting shouts and chants, precise choreography, idol presentation, and theatrical mythology.
None of the three performers came from a conventional metal background.
Yui's official role was: Scream & Dance.
Together with MOAMETAL, she formed the synchronized visual and vocal counterpart to SU-METAL's central lead-vocal role.
The classic original formation placed: SU-METAL in the center, with YUIMETAL and MOAMETAL mirroring each other through dance, calls and supporting vocals.
This symmetry became one of the most recognizable features of early BABYMETAL.
BABYMETAL's first original song, “Doki Doki ☆ Morning,” appeared on Sakura Gakuin's first album, Sakura Gakuin 2010 Nendo ~message~, released in April 2011.
The song and video established the central contrast that later defined the group: extreme guitar and drum textures presented alongside bright melodies, youthful choreography and deliberately cute imagery.
BABYMETAL's early live activity expanded through 2011 and 2012.
The group released: “BABYMETAL × Kiba of Akiba” and “Headbangeeeeerrrrr!!!!!.”
It appeared at SUMMER SONIC in 2012 and performed outside Japan at Anime Festival Asia Singapore.
For Yui, one of the most personally meaningful early concerts was LEGEND “D” in December 2012.
BABYMETAL performed a cover of Karen Girl's “Over the Future.”
Because Karen Girl's had inspired Yui before her own idol career, performing that song on a major BABYMETAL stage represented a direct link between her childhood admiration and her new professional identity.
Yui described the experience as the fulfillment of a dream.
BABYMETAL's major-label debut came on January 9, 2013 with: “Ijime, Dame, Zettai.”
That year created an important structural question.
Suzuka Nakamoto was required to graduate from Sakura Gakuin in March 2013.
If BABYMETAL remained only an internal school club, it should logically have ended with SU-METAL's graduation.
Instead, it was announced in February 2013 that BABYMETAL would continue as an independent project beyond Sakura Gakuin.
Yui and Moa therefore occupied two professional worlds at once.
They remained full Sakura Gakuin members while BABYMETAL developed its own releases, headline concerts and overseas schedule.
The YUIMETAL/MOAMETAL partnership was given a separate identity through: BLACK BABYMETAL.
BLACK BABYMETAL was the duo configuration used when SU-METAL left the stage and Yui and Moa performed their own material.
The first signature song was: “Onedari Daisakusen.”
Its mischievous concept, rap-like delivery and playful choreography gave Yui and Moa more vocal responsibility than the standard trio formation.
Another central BLACK BABYMETAL track became: “4 no Uta.”
The official credit lists: Lyrics — BLACK BABYMETAL Music — BLACK BABYMETAL Arrangement — K×B×METAL and TATSUO.
Because BLACK BABYMETAL consisted of YUIMETAL and MOAMETAL, the song represents an official songwriting credit for Yui Mizuno and Moa Kikuchi.
Yui and Moa explained that the song began as something they made up together during travel before the production team developed it into a complete track.
The wordplay revolved around the number four and its different Japanese readings.
The result became one of the clearest examples of the performers themselves directly originating part of BABYMETAL's recorded material.
On February 26, 2014, BABYMETAL released its self-titled debut album.
It included: “BABYMETAL DEATH,” “Megitsune,” “Gimme Chocolate!!,” “Iine!,” “Doki Doki ☆ Morning,” “Onedari Daisakusen,” “4 no Uta,” “Catch Me If You Can,” “Headbangeeeeerrrrr!!!!!,” “Ijime, Dame, Zettai,” and other early material.
“Gimme Chocolate!!” became the group's international viral breakthrough.
Only days after the album's release, BABYMETAL held two headline concerts at Nippon Budokan on March 1 and 2.
During the first night, Yui fell from an elevated stage section during “Headbangeeeeerrrrr!!!!!.”
She returned to complete the concert.
The incident is often remembered by fans as an example of her determination, but no unsupported diagnosis or injury details should be added to the record.
The Budokan concerts established BABYMETAL as the youngest female act at the time to headline the venue.
The group then launched its first major world tour in 2014.
Yui performed in: France, Germany, the United Kingdom, the United States, Canada, and Japan.
The Paris concert on July 1 included a special YUIMETAL birthday version of “Headbangeeeeerrrrr!!!!!.”
Yui temporarily took the central lead-vocal position while SU-METAL and MOAMETAL supported her.
The performance became known informally as “Yui-banger.”
On July 5, BABYMETAL appeared at Sonisphere Festival at Knebworth in the United Kingdom.
The performance was a decisive international breakthrough because the group faced a large metal-festival audience well outside the protective context of Japanese idol events.
The strong reception demonstrated that BABYMETAL could operate inside the international rock and metal festival circuit.
Later that summer, BABYMETAL supported Lady Gaga on five dates of the North American artRAVE tour.
Yui was still only fifteen years old.
At the same time that this international schedule was growing, she entered her final Sakura Gakuin school year.
On May 5, 2014, Yui was appointed: Produce Chairperson.
The 2014 Student Council consisted of: Moa Kikuchi — Student Council President Yui Mizuno — Produce Chairperson Hana Taguchi — Spirit Chairperson Yunano Notsu — Talk Chairperson
Produce Chairperson was a newly created role.
It matched Yui's interest in how Sakura Gakuin could be presented and developed rather than simply assigning her a conventional vice-president title.
The appointment also recognized that Yui and Moa were the two longest-serving members of that school year and had grown from the smallest transfer students into senior leaders.
The 2014 school year was unusually difficult because BABYMETAL commitments sometimes required Yui and Moa to be absent from Sakura Gakuin events.
The official Sakura Gakuin history, for example, records that both missed TOKYO IDOL FESTIVAL 2014 because of BABYMETAL extracurricular activity, although they appeared through recorded video.
Yui therefore had to balance: Sakura Gakuin leadership, Twinklestars, Mini-Pati, school and lessons, and a rapidly expanding international BABYMETAL tour.
Her 2014 “100 Questions” feature preserved many details of how she presented herself at the time.
She named Karen Girl's as her favorite idol group and Ariana Grande as a favorite overseas artist.
She described her strong feelings for Sakura Gakuin as one of her strengths.
She said that, if she were not an idol, she might want to become a nurse.
She also expressed a wish for a concert featuring every Sakura Gakuin member, including graduates.
Her fondness for tomatoes became one of her most enduring fan-associated traits.
She said she insisted on eating tomatoes whole and chose a fruit tomato as what she would want to eat at the end of the world.
These answers describe Yui in 2014 and should not automatically be treated as her current adult preferences.
Yui's final Sakura Gakuin album was: Sakura Gakuin 2014 Nendo ~Kimi ni Todoke~, released on March 25, 2015.
On March 29, 2015, she graduated at NHK Hall alongside: Moa Kikuchi, Hana Taguchi, and Yunano Notsu.
The ceremony was particularly symbolic because Yui and Moa were the final two members who had entered during Sakura Gakuin's first year.
At graduation, Yui said that she wanted to fulfill both: her dreams as BABYMETAL's YUIMETAL, and her dreams as Yui Mizuno.
That distinction later became important.
Even at fifteen, she publicly understood YUIMETAL and Yui Mizuno as connected but not identical identities.
After Sakura Gakuin graduation, BABYMETAL became her primary professional focus.
In 2015, the group continued expanding through international headline dates and festivals including Reading and Leeds.
Yui's dance partnership with MOAMETAL remained one of the group's central visual anchors.
The second BABYMETAL album, METAL RESISTANCE, was released on April 1, 2016.
It added two new BLACK BABYMETAL songs: “GJ!” and “Sis. Anger.”
“GJ!” used playful rhythmic vocals and sharp synchronized choreography.
“Sis. Anger” placed Yui and Moa's voices against one of BABYMETAL's harshest and most extreme instrumental arrangements.
The album also included: “Road of Resistance,” “KARATE,” “YAVA!,” “Meta Taro,” “Tales of The Destinies,” and “THE ONE.”
METAL RESISTANCE reached No. 39 on the Billboard 200.
On April 2, 2016, BABYMETAL opened its world tour at Wembley Arena in London.
The group became the first Japanese artist to headline the venue.
In July, BABYMETAL appeared at the Alternative Press Music Awards in Ohio and performed with Judas Priest vocalist Rob Halford.
The collaboration placed Yui and Moa beside one of heavy metal's most recognizable singers on an American awards-show stage.
The year culminated on September 19 and 20 with: RED NIGHT and BLACK NIGHT at Tokyo Dome.
Approximately 110,000 people attended across the two concerts.
The setlists included all four principal BLACK BABYMETAL songs: “Onedari Daisakusen,” “4 no Uta,” “GJ!,” and “Sis. Anger.”
The Tokyo Dome production was the original SU-METAL/YUIMETAL/MOAMETAL era at its largest Japanese scale.
Late 2016 and 2017 took BABYMETAL still deeper into the international metal touring system.
The group performed support dates or special appearances connected with: Red Hot Chili Peppers, Metallica, Guns N' Roses, Korn, and other major artists.
Yui's role required exceptional physical consistency.
BABYMETAL's performances were constructed around demanding choreography delivered across arena stages, outdoor festivals, long tours, flights and rapidly changing climates.
The YUIMETAL/MOAMETAL synchronization remained central to the group's identity throughout this period.
Yui's final completed BABYMETAL concerts were the BIG FOX FESTIVAL shows at Osaka-jō Hall on October 14 and 15, 2017.
She did not appear at: LEGEND – S – BAPTISM XX – in Hiroshima on December 2 and 3, 2017.
The official explanation was poor physical condition.
BABYMETAL proceeded with SU-METAL and MOAMETAL rather than canceling the two concerts.
At the time, no diagnosis or detailed medical explanation was made public.
Yui remained absent when BABYMETAL returned to live activity in May 2018.
The United States tour began without her, and the lack of a clear advance explanation created considerable uncertainty among fans.
An American management representative stated during the tour that YUIMETAL remained a member but was not participating in those dates.
She was also absent from the European shows that followed.
BABYMETAL used changing formations and additional dancers during the 2018 “Dark Side” period.
On October 19, 2018, BABYMETAL officially announced YUIMETAL's departure.
Yui's own message explained that she had wanted to return to the stage but that her physical condition was still not fully restored.
After considering the decision repeatedly, she chose to leave BABYMETAL.
She apologized to the members and supporters affected by her long absence and expressed gratitude for the experiences she had received as YUIMETAL.
She also said that she wanted to move toward her dream as Yui Mizuno.
The group announced that BABYMETAL would continue under a new structure centered on SU-METAL and MOAMETAL.
The departure ended almost eight years of the original trio.
It is important to state the limits of the public record.
Yui and Amuse confirmed a health problem and an incomplete recovery.
They did not identify the condition.
Claims that she had a particular disease, injury, treatment, family problem, body-image issue or private conflict remain speculation unless supported by a direct statement.
The responsible biographical formulation is therefore: YUIMETAL left BABYMETAL because her health had not recovered sufficiently for her to return, while also choosing to pursue a future as Yui Mizuno.
After October 2018, Yui withdrew almost completely from public entertainment activity.
She remained listed as an Amuse artist, but no solo debut, acting role, recording, concert, social-media account or formal comeback was announced.
This long silence led to constant fan speculation.
However, several rare and verifiable traces showed that she remained in contact with people connected to Sakura Gakuin.
Rare confirmed public traces after BABYMETAL
August 2020 — Aiko Yamaide's livestream
On July 31, 2020, former Sakura Gakuin member Aiko Yamaide held an online one-man concert.
During a LINE LIVE broadcast on August 1, Aiko said that Yui had watched the online concert and had told her so.
Aiko referred warmly to Yui as someone she loved and said she was happy that Yui had watched.
This was noteworthy because it was current information rather than an old photograph or recycled anecdote.
The statement confirmed recent contact between Aiko and Yui and confirmed that Yui had followed Aiko's music activity at that moment.
It did not constitute a public appearance by Yui and did not reveal her health, occupation or plans.
March 2021 — Sakura Gakuin 10th Anniversary Memorial Book “Thank you…”
Yui contributed answers to Sakura Gakuin's tenth-anniversary memorial book.
They were her first substantial public words since her 2018 BABYMETAL departure message.
Among the memories and opinions she shared:
She selected the surprise field trip used to film the “FRIENDS” music video as one of her most precious Sakura Gakuin memories.
She remembered the members reading paired letters to each other and the fun of going to the farm together.
She said Sakura Gakuin songs could make her smile by bringing back memories of making eye contact with particular members during particular sections.
Her favorite song from her own membership period was “Yume ni Mukatte.”
Her favorite later song was “Identity.”
She revealed that younger members sometimes contacted her about new songs and let her see lyrics or hear the music, which she jokingly described as a graduate's privilege.
Asked what she would tell her younger Sakura Gakuin self, she answered that she was doing fine and should continue as she was.
She described a “Super Lady” as a compassionate and dignified person.
In her anniversary message, she said that the members, staff, juniors and supporters remained a source of courage and that she wanted to use what Sakura Gakuin had taught her in the rest of her life.
The wording focused on life broadly rather than announcing any entertainment project.
August 2021 — Sakura Gakuin final-concert message display
Sakura Gakuin held its final concert, Sakura Gakuin The Final ~Yume ni Mukatte~, at Nakano Sun Plaza on August 29, 2021.
A large commemorative handwritten message display — sometimes described by fans as the final mural or farewell wall — was shown in connection with the concert.
It included messages and signatures from graduates, including Suzuka Nakamoto, Moa Kikuchi, Yui Mizuno, Kano Fujihira and Momoko Okazaki.
Yui's message appeared toward the lower-left area of the display and was signed: 水野 由結
Her message read: “Sakura Gakuin shines dazzlingly within my heart, now and forever. Thank you!”
The Japanese text was: さくら学院は私の心の中で 眩しいくらいに光っています。 今でも、これからもずっと!! ありがとう Thank you…
The message was important because it demonstrated Yui's continuing emotional connection to Sakura Gakuin ten years after joining and more than three years after leaving BABYMETAL.
It should not be used as proof that she personally attended the final concert.
The confirmed fact is that her handwritten message and signature were included in the final commemorative display.
2022–2024 — continued privacy
No public entertainment project was announced for Yui during these years.
Amuse continued to maintain an artist profile for her, but representation alone did not mean that a comeback had been scheduled.
Occasional references by friends, former members or fans were not substitutes for a direct professional announcement.
September 2025 — departure from Amuse and the entertainment world
On September 30, 2025, Amuse announced that Yui Mizuno was leaving the agency that day.
The company explained that it had held repeated discussions with her and had decided to respect her wish to step away from the entertainment world and live life at her own pace.
Amuse thanked the fans and people who had supported her and said that it would continue wishing her well in the next part of her life.
This announcement resolved the ambiguity that had existed since 2018.
Yui was no longer simply an inactive Amuse artist waiting for an announced project.
She had chosen to leave entertainment and prioritize a private life.
As of August 29, 2026: she has no announced agency, no current group, no official public social-media account, and no announced return to music, acting or performance.
Her privacy should be respected.
Yui's career is unusual because its public importance is much larger than its chronological length might suggest.
She performed professionally as YUIMETAL for fewer than eight years, but those years covered BABYMETAL's entire transformation from a Sakura Gakuin club unit into a global arena and festival act.
She was present for: the creation of the Heavy Music Club, “Doki Doki ☆ Morning,” the first BABYMETAL headline concerts, the separation from Sakura Gakuin, the viral spread of “Gimme Chocolate!!,” Nippon Budokan, Sonisphere, Lady Gaga's artRAVE, the first world tours, Wembley Arena, the Rob Halford collaboration, Tokyo Dome, and the major support tours of 2016–2017.
Her most important artistic contribution was not only that she occupied the left or right side of a three-person formation.
The visual logic of original BABYMETAL depended heavily on the precise relationship between YUIMETAL and MOAMETAL.
Their mirrored choreography created: scale around SU-METAL, rapid visual movement, contrast between the central vocal and supporting pair, and a recognizable identity that could be understood even by audiences hearing the music for the first time.
BLACK BABYMETAL also allowed Yui to show a different performance mode.
In the full trio, her vocals were often used for: chants, responses, short melodic lines, and rhythmic emphasis.
In BLACK BABYMETAL, she and Moa carried entire songs together.
“Onedari Daisakusen” emphasized theatrical comedy.
“4 no Uta” preserved their own creative wordplay and official songwriting credit.
“GJ!” emphasized rhythm and movement.
“Sis. Anger” placed their voices inside a particularly severe metal arrangement.
The fan image surrounding Yui also developed from several recurring traits: her highly controlled dance, her quiet or careful speaking style, her love of tomatoes, her attachment to Karen Girl's, and the contrast between her gentle offstage image and intense stage focus.
Fans sometimes used nicknames such as “Yui-bot” to praise the mechanical precision of her dancing.
They also popularized “YMY” — “Yui Metal Yui” — as an expression of loyalty to her.
These are fan-culture terms rather than official positions or titles.
Yui's later story also requires restraint.
The absence of public information is not an invitation to fill the record with theories.
The most accurate conclusion is simple:
Yui Mizuno made a lasting contribution to Sakura Gakuin and to BABYMETAL's founding era.
She left BABYMETAL after a prolonged health-related absence.
She maintained a private connection with Sakura Gakuin and some former members, as shown by Aiko Yamaide's 2020 comment and Yui's own 2021 messages.
In 2025, she formally chose a life outside entertainment.
Her current life is private, and there is no confirmed basis for predicting a comeback.
Career progression
Child reader model → commercial and acting work → Sakura Gakuin transfer student → Twinklestars → BABYMETAL Heavy Music Club / YUIMETAL → Mini-Pati → saku saku chart girl → BLACK BABYMETAL → Sakura Gakuin Produce Chairperson → full-time BABYMETAL performer → international arena and festival artist → health-related absence → departure from BABYMETAL → privately represented by Amuse without announced activity → retirement from entertainment / private life.