Spring Mustachio is an A-Class hero and a gifted swordsman trained by the master swordsman Nichirin. Lean-built with short black hair combed to one side, curled sideburns, yellow eyes, and his namesake thick handlebar mustache, he's an intelligent, serious fighter who doesn't back down — he kept fighting Kombu Infinity even after taking a serious beating.
He's part of one of the Hero Association's more effective monster-hunting duos, regularly pairing his close-range swordsmanship with fellow A-Class hero Golden Ball's long-range attacks; off duty, the two are shown sharing drinks together as genuine friends rather than just battlefield partners.
A tall, slender, aristocratic man with short black hair and a long, thin, meticulously groomed mustache he frequently twirls. Almost always in a formal black tuxedo with white shirt and bowtie, carrying a rapier disguised as a walking cane.
Sophisticated, calm, and formally spoken, with a strong sense of hero etiquette and martial honor. Deeply loyal to his master Nichirin’s teachings — he’s moved to tears when Nichirin recognizes his growth — and shares an easy, casual camaraderie with his best friend Golden Ball off duty.
A “genius swordsman” from a prestigious fencing school, and a top disciple of Nichirin, leader of the Council of Swordsmen (Holy Order of the Sword). Eventually applied his skill to professional hero work, rising to Class A.
First appears investigating monster rumors in City Z’s Ghost Town with Golden Ball, where the two are badly beaten by Kombu Infinity. During the Hero Hunter Arc, he traps Garou in an alley with his “Tomboy” thrust technique, only to still lose the fight. During the Monster Association raid, he fights alongside Nichirin, Atomic Samurai, and Iaian against the endlessly dividing Black Sperm, witnesses Nichirin’s death, and is formally named a “Master” by him before he dies.
Master Fencer: capable of hundreds of precision stabs per second. Tomboy: a concentrated thrust that unfurls the hidden “spring” in his blade, piercing reinforced concrete and solid steel. His rapier doubles as a cane for concealed carry. Early weakness: struggled with his long blade in tight spaces before mastering ways to compensate.
vs. Kombu Infinity — Ch. 20–21
Investigated City Z's Ghost Town and fought valiantly, but the monster's reach was too much — he was defeated and hospitalized.
vs. Garou — Ch. 48
Cornered the Hero Hunter in an alleyway and used the terrain to trap him with a flurry of thrusts, but Garou eventually read through it and won.
vs. Black Sperm — Ch. 151–155
Held off thousands of Black Sperm clones on the surface alongside Atomic Samurai's disciples using pure high-speed fencing.
The Death of Nichirin — Ch. 155
Watched his master die from his wounds — but not before Nichirin formally named him a “Master” of their swordsmanship school.
Major: Ch. 20, 48, 151, 155. Minor: Ch. 21, 62, 67, 81, 156. Mentioned only: Ch. 63, 68, 114, 186.
Golden Ball: best friend and regular mission partner. Nichirin: mentor and father figure, source of his entire fighting philosophy. Atomic Samurai: a senior swordsman he deeply respects. Garou: the enemy who defeated him in the alley.
“Do not be so sure... the sword is not unwieldy.” — to Garou
“Master...” — at Nichirin’s final acknowledgment
Considered one of the few Class A heroes with technical skill that could rival lower S-Class members. His hero name references both his mustache and the “spring-like” nature of his rapier.
🇯🇵 Japanese Voice Actors
Yasumura, Makoto
🇯🇵 Japanese
🇺🇸 English Voice Actors
Collins, David W.
🇺🇸 English