The Subterranean King is the ruler of the Subterranean People, leading them up from below the earth's crust in an attempt to conquer the surface. His body is covered in dark brown armor plating with visible lava flowing between the segments, and he has three narrow, glowing purple eyes — two set diagonally and one vertical in the center — along with a distinctive half-circle-shaped head that marks him out from his subjects. He wields four arms, each ending in three clawed fingers, and carries a magma sword in each hand.
For all his fearsome design, his reign is over almost as soon as it begins: Saitama ends the fight with a single kick, killing him instantly and leaving his subordinates to scatter back underground without him.
Two versions: in Saitama’s dream, a colossal, black-skinned, glowing-eyed, four-armed warrior with a jagged crown-like horn and tribal flame patterns, wielding four massive swords. In reality, roughly human-sized, leaner, with bulging bug-like eyes and four simple knives instead. Both versions wear a loincloth with dark ornate gauntlets and greaves.
In the dream, a noble, honor-driven warrior who takes pride in his race and genuinely respects Saitama as an opponent. In reality, simply arrogant and overconfident, viewing surface dwellers as obstructions in the way of his race’s expansion.
Led a hidden subterranean civilization for centuries, claiming his race had “proliferated” past what the underground could sustain. Later discoveries (Ch. 115–131) suggest his people once inhabited the ruins that became the Monster Association’s hideout, complete with a sacrificial altar hinting at subservience to older, more powerful entities.
In Saitama’s dream, he appears after Saitama has already cut through thousands of his soldiers, and gives him a genuinely thrilling one-on-one duel. Saitama wakes up mid-fight to find the real King kicking down his door; before the King can finish his ultimatum, Saitama kicks him once, killing him instantly. His subjects immediately surrender with a “Sorry” sign. His death is later cited by Sky King as clearing the way for further invasions.
In the dream, a four-sword style fast enough to match Saitama. In reality, strong enough to kick down reinforced doors, plus the Subterraneans’ shared tunneling ability — but nowhere near durable enough to survive a single real hit.
vs. Saitama (Dream) — Ch. 4
Led the invasion of Saitama's neighborhood in a dream, giving Saitama a rare taste of a fight he actually felt something in — cut short when he woke up.
vs. Saitama (Reality) — Ch. 4
The real King barely got through his opening monologue before Saitama one-shotted him with a kick — a comedic subversion of the dream that came before it.
Major: Ch. 4. Minor: Ch. 18. Mentioned only: Ch. 32, 115, 128, 142.
Subterraneans: his loyal subjects, who fled the instant he died. Saitama: ended his reign in a single hit. Sky King & Deep Sea King: rival monarchs who tracked his death as a shift in the balance of power.
“I - the Subterranean King - will fight you!” — dream version
“All surface dwellers will die! Mwa ha ha! We Subterraneans have claimed the Earth!” — real version, final words
The first of the series’ “elemental kings” to appear and fall. His death is one of the fastest in the series — occurring just panels after his real-world debut.
🇯🇵 Japanese Voice Actors
Ueda, Youji
🇯🇵 Japanese
🇺🇸 English Voice Actors
Thornton, Kirk
🇺🇸 English