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Fish of Darkness (ヤミ金魚, Yami Kingyo) is a Mysterious Being and the head of Niya Niya Loans.



Fish of Darkness as human

As a human, he was light-skinned with light brown, combed back hair, short facial hair, and wore a dark purple suit with a light purple, almost white shirt underneath with frilled sleeves. He also wore two white scarf ties around his neck, multiple rings, and large circular sunglasses.

As a Mysterious Being, he becomes a pink, anthropomorphic fish wearing black BDSM equipment.


Road to HeroEdit

Mysterious Being Transformation

His transformation to a Mysterious Being

As a human he had an impulsive desire inside him to buy out all the stores in Z-City, through his criminal organization that was based in Saitama's old apartment complex. After Saitama figured out their base, he beat up all his lackeys and was informed that Saitama was heading to confront him. After Saitama angered him, he triggered his transformation into a Mysterious Being called Fish of Darkness. After a brief battle, he lost against Saitama and was handed over to the police for a reward.

Abilities and PowersEdit

Fish of Darkness is a fairly powerful being. He was strong enough to give Saitama some trouble, albeit this was still while he was in his early stage of training, and he was quickly defeated after Saitama became pumped up for the reward money.

Physical AbilitiesEdit

Enhanced Speed: Fish of Darkness is fairly fast. He is able to attack with his whip in rapid succession.

Egg (Ballgag) Spit: Fish of Darkness demonstrated the ability to shoot out eggs (ballgags) from his mouth.


Whip: Fish of Darkness uses a whip. He is fairly skilled with it as he was able to give Saitama a hard time, but it should be noted that Saitama was still fairly weak at this time.


  • Fish of Darkness is the first Mysterious Being whose transformation process was shown on screen, although the "transformation" process was quite different from other transformations shown later in the series.
  • When he saw Fish of Darkness take on his new risqué outfit and appearance, Saitama doubted that the man had actually transformed from a human into a monster like he had intended to, due to Saitama having previously watched a program on television about how organisms undergo metamorphosis. Instead, Saitama hypothesises that, rather than being a monsterized human, Fish of Darkness was merely a weirdo who had become an even weirder weirdo, thereby becoming a pervert. It is unknown whether there is any truth to Saitama's conjecture.


Mysterious Beings
Unaffiliated Crablante Vaccine Man Marugori Piggy Bancon Giant Snowman Himawari Personification Of A Light Pull Cord Kombu Infinity170,000-Year-Old Cicada Larva 170,000-Year-Old Cicada Adult Demonic Fan Delorean Alien SeerThree-Eyed Ghost Surprise-Attack Plum Tongue StretcherGiant Crow Octopus Claw Man Grizzly Nyah Suppon Gigakigan Hotdog Game-Berus Autumn Phantom Red Golden-ringed DragonflyJumping Spider Scaledon Enamel Black Roast Macho Daikon Withered Sprout Twin-Headed Tsuchinoko Man-Eating Capybara Pot Bellee Kenzan Rat Pesky Clown
Native Tribes Forest Tribe (Forest King ) • Seafolk (Deep Sea King Lord Great White Messenger of the Seafolk ) • Skyfolk (Sky King Eagle Hawk Falcon Kite ) • Subterranean People (Subterranean King ) • Terror Lizard Clan ( Ancient King )
Dark Matter Thieves Boros Geryuganshoop Melzargard Groribas Dark Matter Gunner 
The Organization G4 G5 
House of Evolution Carnage Kabuto Beast King Armored GorillaKamakyuri Ground Dragon Frog Man Slugerous Mosquito Girl 
Anime-Only Mysterious Beings Super Custom YO649Z Mk. II Fish of Darkness *Pluton Men's Esthetician Man *Dirt Earthworm Japanese Giant Salamander Lord of Mountains TV Junkyard Monster Urn Eel Crazy Brown Bear 
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