Zenko

Zenko (ゼンコ, Zenko) is Metal Bat's little sister.

Appearance
Zenko is a young child with similar facial features to her older brother. She wears a light colored cardigan and frock. She wears black flats and white high socks with frills. She has shiny Showa era hair style black hair which she keeps around chin-length and clips it aside with a floral clip.

Personality
Zenko is just as strong-willed and headstrong as her brother, but dislikes violence. She is caring and very protective of her brother. In addition, she is quite fearless as she was willing to go into an evacuated city during a monster crisis and was unafraid to stand up to Garou. Like her brother, she's very hot-headed, to the point of even arguing with Garou despite risking both her life and her brother's. However, she is also quite humble, refusing to boast about her hero brother in front of other schoolkids.

Alien Conquerors Arc
Zenko has a piano recital during the alien invasion. She later calls Metal Bat, when he is arguing with Sweet Mask. She also asks for Sweet Mask's autograph.

Hero Hunt Arc
She calls her brother to ask for help to carry her shopping bags, but Metal Bat declines because he is too busy. This causes her to cry and hang up.

Monster Raid Arc
When Metal Bat is about to hit Garou, she shouts, "Big Brother!". Noticing that his sister is here, he stops his swing centimeters away from Garou's face. Garou takes this opportunity to punch Metal Bat and before the two could clash again, Zenko jumps right in front of Metal Bat and covers him in a protective stance. She then risks her life for her brother and tells Garou about her promises with Metal Bat. Garou listens, respects her wishes and accepts her persistence for anti-violence. He then quickly makes up an excuse and leaves the siblings alone.

After a brief conversation with her brother about how she knew where Metal Bat was, Metal Bat tries to go back to fighting Elder Centipede. Frustrated that she is unable to convince him otherwise, Zenko smacks him on the back of his head, which unintentionally knocks him unconscious. She then tries to drag her brother home.

Super Fight Arc
She is later seen watching over Metal Bat as his injuries are being treated.

Monster Association Arc
Zenko visits her brother in the hospital and watches the news about the Monster Association.

Abilities and Powers
According to her older brother Metal Bat, she is able to play the piano. She also appears to be quite skilled in it, as she got into the 3rd place in the piano concert she was in.

Physical Abilities
Enhanced Speed and Reflexes: Zenko is surprisingly fast, as she was able to intervene between Garou and Metal Bat before they were able to clash again. Moreover, she is capable of jumping fairly high for a child, as shown when she jumped to reach her brother's head in order to hit him.

Enhanced Strength: Zenko can easily hold a flower bouquet that is almost as big as her brother with one arm.

Trivia

 * Zenko (ゼンコ, Zenko) means expressive, diplomatic, and refined nature, which can be seen when she tries to negotiate a resolution with Garou.
 * Murata stated that Zenko is a lot like his own daughter, who also takes piano.