Beast King is an artificial mutant created by Dr. Genus of the House of Evolution, leading Genus's strike force as the second-strongest of the lab's creations — outmatched only by Carnage Kabuto. He's a massive, humanoid lion with a full mane and tail, five-fingered hands tipped with sharp claws, and heavy chained furs and bracers across his body that he shatters outright once enraged.
Loud and constantly roaring his dialogue, Beast King genuinely revels in his own strength, which makes Saitama's calm, fearless resistance to it deeply unsettling to him. As a leader, he's openly sadistic and dismissive of his fellow mutants' lives — when his own stray attack accidentally kills allies Slugerous and Frog-Man, he shrugs it off as simply the "law of the jungle."
A colossal, anthropomorphic lion towering over an average human, with a massive muscular frame in tawny fur, a voluminous dark mane, predatory eyes, and enormous obsidian-colored extending claws. Wears a primitive leopard-print kilt and heavy chains draped across his shoulders and torso.
Arrogant, vicious, and ruthless, taking real pride in his “King” status as the ultimate predator. Severely overconfident and short-tempered, with little patience for subordinates’ mistakes — he once threatened to kill Ground Dragon over a tactical slip.
An artificially evolved House of Evolution creation, ranked the organization’s #2 warrior behind only Carnage Kabuto, leading missions to secure resources or eliminate threats to Dr. Genus’s research.
Leads the five-member strike team sent to capture Saitama. After Ground Dragon immobilizes Saitama in the ground, Beast King mocks him as a "failure of a species" and unleashes a barrage of vacuum-blade claw strikes that shred nearby buildings — all dodged effortlessly. In desperation he attempts a full-power Lion Slash, but Saitama counters with Consecutive Normal Punches, instantly obliterating his upper torso and killing him — the first time that technique appears in the manga.
Lion Slash (獅子斬り): rapid claw strikes that generate vacuum blades capable of cutting through concrete and steel at range. Enhanced physicality far beyond standard monster levels and enough tactical skill to coordinate a multi-pronged ambush — but nowhere near enough durability to survive Saitama’s counterattack.
vs. Saitama — Ch. 8
Attempted to capture, then kill, Saitama with his Lion Slash techniques. Total defeat — the fight that gave Dr. Genus the data proving Saitama wasn't a normal hero, and the first time Saitama used Consecutive Normal Punches in the manga.
Major: Ch. 8. Mentioned only: Ch. 9, 32, 38, 234.
Dr. Genus: his creator, followed without question. Armored Gorilla: his subordinate, treated with cold professional distance. Carnage Kabuto: his acknowledged superior within the House of Evolution. Saitama: the "inferior specimen" who killed him.
“I’ll show you the power of the Beast King! Lion Slash!”
“You’re just a failure of a species!”
Saitama later references the Consecutive Normal Punches he used on Beast King while playing video games against King. Unlike Armored Gorilla or Mosquito Girl, he was definitively killed and never reappears in later arcs.
🇯🇵 Japanese Voice Actors
Saitou, Jirou
🇯🇵 Japanese
🇺🇸 English Voice Actors
St. Peter, Paul
🇺🇸 English