Iaian is an A-Class hero and the top-ranked disciple of Atomic Samurai, alongside fellow disciples Okamaitachi (Rank 3) and Bushidrill (Rank 4) — together forming Atomic Samurai's team of elite swordsmen. Quick-tempered and quick to act, he responds to any attack against him with immediate, in-kind force, and was visibly enraged by the widespread destruction of A-City during the Alien Conquerors arc, calling it unforgivable.
His most notable individual moment comes in the aftermath of that attack, when he saves a father and son from being killed by the alien general Melzalgald as the father claws through rubble to reach his trapped child — a rare glimpse of Iaian's principles overriding his usual battle-focused demeanor.
A muscular young man with short spiky blond hair and intensely focused eyes, wearing a full suit of silver, medieval-style knight’s armor and carrying a long katana for his signature Iai draws. After losing his left arm during the Alien Invasion, he wears the empty sleeve pinned into his chest plate.
Serious, stoic, and thoroughly professional, with absolute reverence for Atomic Samurai as “Master.” Genuinely selfless — he prioritized civilian safety over his own medical treatment right after losing his arm — and humble enough to openly admit how far he still is from S-Class.
Trained since his formative years under Atomic Samurai alongside fellow disciples Bushi Drill and Okama Itachi. Reached Class A Rank 2 and has stayed there for a long stretch, blocked from S-Class only by Amai Mask’s refusal to vacate the top Class A spot.
The first hero to engage the alien executive Melzalgald in City A; loses his left arm to a surprise shapeshifting strike but cauterizes the wound with his own blade and keeps fighting until backup arrives. Later monitors the Hero Hunter threat alongside his master’s Council of Swordsmen. During the Monster Association raid, leads the surface support team against Rhino Wrestler, then infiltrates the base with Bushi Drill and Okama Itachi to rescue the Narinki Private Squad and defeat the Demon-level Devil Long Hair as a synchronized trio. Afterward, joins his fellow disciples in investigating Amai Mask’s suspicious history.
Master of Iaijutsu — drawing and striking in a single, extremely fast motion, capable of multiple hits before an opponent can react, even one-armed. High pain tolerance and strong tactical leadership. Explicitly noted as unable to solo Dragon-level threats without support from his master or fellow disciples.
vs. Melzalgald — Ch. 32
Fought the alien executive alone and got caught off guard by its shapeshifting regeneration — lost his left arm for it, but the fight showed just how far he was willing to push.
vs. Rhino Wrestler — Ch. 94
Challenged the monster's claimed “100-point” durability directly. Ended in a draw when Atomic Samurai stepped in — but Iaian's precision strikes did damage where standard Class A heroes couldn't scratch it.
vs. Devil Long Hair — Ch. 112
Fought alongside the other Three Disciples deep in the Monster Association base and won — proof the three of them together approach S-Class-level power.
Major: Ch. 32, 94, 103, 112, 121, 175. Minor: Ch. 31, 33, 34, 37, 69, 104, 131, 142, 180, 186. Mentioned only: Ch. 38, 220, 234.
Atomic Samurai: his mentor and idol. Bushi Drill & Okama Itachi: fellow disciples he fights with near-telepathic coordination. Amai Mask: a rival of sorts, respected but resented for blocking his path to S-Class. Spring Mustachio: a fellow swordsman he respects and worried over after his defeat by Garou.
“My killer slashes haven’t brought him down... is he invulnerable?” — on Melzalgald
“I’m still a long way from Class S...”
Officially stated that Iaian and his fellow disciples would likely be promoted to S-Class if Amai Mask weren’t occupying the top Class A spot. Witnessed King’s “apple incident” and, like Atomic Samurai, misread it as a display of superhuman speed.
🇯🇵 Japanese Voice Actors
Hosoya, Yoshimasa
🇯🇵 Japanese
🇺🇸 English Voice Actors
Mobus, Xander
🇺🇸 English