Zenko

Name: Zenko

Gender: Female

Special Skill: Piano

Voice Actress (anime/remake): Ayumi Mano

Zenko is the younger sister of Bad, the S-Class Rank 16 hero better known as Metal Bat.

She is an ordinary schoolgirl on the surface, but her personality and actions make her stand out in the hero-filled world around her.

She is first mentioned only in Bad’s dialogue as his younger sister.

She later makes her on-page debut in Yusuke Murata’s remake version, in Chapter 87.

Despite the large age gap, Zenko is one of the few people Bad cannot defy, and he listens seriously when she speaks.

She has a strong personality and does not hesitate to scold her brother when she thinks he is going too far.

Zenko is tough-minded and fearless, especially for her age.

She steps in between Bad and Garou, refusing to back down even when Garou is about to finish her brother off.

Her bravery is not loud or flashy; she simply acts when she feels something is wrong.

This calm boldness impresses even in a world full of monsters and heroes.

At school, she does not boast about her brother being an S-Class hero.

Instead, she cherishes him purely as her “big brother,” seeing him as family first and a hero second.

Zenko is very affectionate and loyal.

She admires Bad more than anyone and worries deeply about his safety, even when he brushes off danger.

She also has a slightly fangirl side.

She once asked her brother to get an autograph from Sweet Mask, showing that she can still get excited over popular heroes and celebrities.

Zenko is not officially a hero and has no known special combat training.

However, she shows hints of surprising physical strength and potential.

On the back cover of Volume 11 of the manga, she is depicted casually holding, with one hand, the huge bouquet that Bad brought to her piano recital.

The flowers are large and heavy enough that an ordinary child would struggle, suggesting Zenko may have latent physical power similar to her brother’s.

Combined with her fearless temperament and moral backbone, this has led some fans to speculate that Zenko could have the makings of a future hero.

While the series has not formally developed her into a fighter, the small hints make her an intriguing “hidden gem” type character.

Zenko and Bad share one of the most heartfelt family relationships in One-Punch Man.

Bad’s rough, delinquent-like appearance softens completely whenever Zenko is involved.

For Bad, attending Zenko’s piano recitals is one of his greatest joys.

No matter how battered he gets in battle, he is motivated by the desire to return home safely to her.

Zenko, in turn, respects Bad as a person rather than as an S-Class hero.

Her refusal to brag about him at school shows that she values their bond more than status or fame.

When she intervenes in Bad’s fight with Garou, her presence is the only thing strong enough to make Bad stop fighting.

This scene emphasizes how central she is to his emotional world and highlights her role as his moral anchor.

Zenko’s main hobby and talent is playing the piano.

She takes piano lessons and participates in recitals, where she performs in front of an audience.

Her recitals are events Bad looks forward to, offering a peaceful contrast to his brutal hero work.

These scenes help ground the story, reminding readers that even in a monster-filled world, everyday childhood moments still matter.

Outside of music and school, Zenko behaves like a typical girl of her age.

Her interest in Sweet Mask’s autograph shows she follows popular culture and idolizes cool heroes just like many kids.

In the remake version illustrated by Yusuke Murata, Zenko makes her first physical appearance in Chapter 87.

Prior to that, she is only referenced indirectly through Bad’s dialogue.

She later appears in additional scenes focusing on Bad’s personal life and family background.

These moments deepen the audience’s understanding of Bad by showing who he is when he is not swinging a bat at monsters.

In the original webcomic version, Zenko remained off-screen for a long time.

In Chapter 152 of the original version, updated in January 2025, she finally appears in the source material itself, even if only for two panels.

This brief but important appearance officially brings her into both the remake and original continuities.

It signals that her role, while small, is recognized as canon in both versions of One-Punch Man.

Zenko’s calm intervention in the fight between Bad and Garou is one of the rare moments where a non-hero child stops a high-level battle.

Her words and presence are powerful enough to override Bad’s fighting spirit and Garou’s bloodlust.

Her casual one-handed grip on the huge bouquet at her piano recital has become a popular fan talking point.

Many fans jokingly suggest that she might secretly be as physically gifted as her brother or at least possess some unusual durability.

Although she admires Sweet Mask enough to ask for his autograph, Zenko clearly loves Bad far more.

Her priorities show that, for her, family bonds outweigh celebrity status or hero rankings.