One-Punch Man Wiki
You're looking down on me, aren't you?
— To Atomic Samurai[1]

This article is about Black Sperm. For the fusions of trillions of cells, see Golden Sperm and Platinum Sperm.

Black Sperm (黒い精子, Kuroi Seishi; Viz: Black Spermatozoon) is a Dragon-level Mysterious Being and an executive member of the Monster Association.

Warning.png Expand to see original webcomic information. Beware of spoiler content.

After the Monster Association's downfall, Black Sperm becomes Saitama's pet, alongside Overgrown Rover,[2] and is currently under the watch of Forte, Chain'n'toad, and Butterfly DX.[3] He is also one of the few individuals aware of Saitama's strength, due to witnessing him defeat Garou.[4]


Black Sperm is an odd-looking humanoid monster of diminutive stature. He has a completely black body and a pale, white face with black eyes and a tail-like protrusion on the top of his head. He is often portrayed in a more simplistic style than the other characters, reminiscent of ONE's original webcomic.


Black Sperm expressing anger whenever somebody looks down on him

Black Sperm is an arrogant yet insecure monster. He is very confident in his abilities, shown in his willingness to take on Monster King Orochi,[5] but he dislikes when other people "look down on him" for his appearance or personality, and if he senses that someone is doing so, he becomes furious.[1] At the same time, he is willing to work with others in order to take on a stronger opponent, shown by his cooperation with the Monster Association.

Black Sperm also shows great anger if his clones are killed.[6][7]

Black Sperm simultaneously feeling extreme joy and sadness as he witnesses Platinum Sperm being born

During the battle against the heroes, Black Sperm shows impatience and anger when his enemies are effectively fending off him such as Superalloy Darkshine and the Council of Swordmasters.[8] However; he still remains confident and sadistic when gaining the upper-hand against Genos.[9][10] When facing King, Black Sperm is unwilling to aid Homeless Emperor and stays on his guard, fearing that the S-Class hero might strike him if he loses his focus.[11] Black Sperm also feels great sorrow and joy at the same time when Platinum Sperm is born as a result of 53,999,999,999,900 of his cells being sacrificed, expressing that while those huge amount of cells are disappearing into nothingness, that also marks the birth of his real self.[12]

Warning.png Expand to see original webcomic information. Beware of spoiler content.

Like other monsters, Black Sperm appears to care little for the lives of humans as he was about to kill the child kidnapped by the Monster Association without remorse. Likely due to his nature, he is accustomed to teamwork and is often the one to suggest teaming up with the other executives to take on strong enemies such as Tatsumaki. As more sperm cells merge together, the newly formed cell copies become more and more arrogant.

After being defeated by Garou and then witnessing Saitama defeat Garou in turn, Black Sperm is humbled greatly. He begins to patiently bide his time and slowly build his cell stock back up over time. He decides to stick around with a stronger being, which happens to be Saitama in this case, rather than go off on his own.

Abilities and Powers[]

As a Dragon-level Mysterious Being and an executive member of the Monster Association, Black Sperm is an extremely powerful being. He was able to easily overwhelm the S-Class hero Atomic Samurai during their battle due to his abilities being the perfect counter to the hero's fighting style.[1] Furthermore, Black Sperm is capable enough to cause Psykos to remark that if he and Homeless Emperor team up together, they can defeat anyone.[13] According to Homeless Emperor, a single Black Sperm clone is strong enough to easily defeat an A-Class hero.[14]

Physical Abilities[]

Black Sperm bursting out of the ground

Immense Strength: Contrary to his appearance, Black Sperm possesses great strength. A single copy was strong enough to significantly injure Atomic Samurai, an S-Class hero, in one hit, and with overwhelming numbers of copies, he was able to subdue the powerful swordsman in no time during their battle.[1] In his larger state, he has shown capable of restraining Sweet Mask, the top-ranked A-Class hero with S-Class capabilities,[15] and embedding Genos into the ground with a single strike.[16] Smaller copies of himself are even able to tear off Genos' limbs.[17][18]

Enhanced Speed and Reflexes: Black Sperm possesses impressive speed and agility, as demonstrated when a copy of himself managed to react to and dodge an air slash from Atomic Samurai, prompting the swordsman to remark that he was a swift monster.[19] Additionally, a Black Sperm clone, consisting of only 100 cells, was also fast enough to swiftly evade several swings from Metal Bat.[20]

Shapeshifting: Black Sperm is able to increase in size and manipulate his body shape in any way he chooses such as manifesting multiple heads or limbs.

Black Sperm splitting into even more copies after being cut to pieces by Atomic Samurai

Replication: Instead of being killed, whenever he is dealt a fatal blow that would typically result in death, Black Sperm will split into even more copies of himself if he still has enough cell stock.[1] He can also split himself at will.[22][23] However, he is still susceptible to attacks that do not immediately cut him to pieces, such as blunt force[24] or acid attacks.[25]

Regeneration: Black Sperm possesses a unique regenerative ability; as his body is formed from vast numbers of copies of himself working together, any damage he sustains will reduce his total count but his body is able to fully regenerate so long as he has reserves. Even if he is cut to pieces, his severed body parts will reform into more copies of himself.

Fighting Style[]

Proficient Hand-to-Hand Combatant: Black Sperm often relies on brute strength and overwhelming numbers to defeat opponents. However, according to Drive Knight, he is a highly skilled combatant.[26]

  • Sperm Tsunami (精子津波, Seishi Tsunami; Viz: Spermatozoon Tsunami): Black Sperm rapidly splits up to overwhelm and crush his opponents.[27]

Golden Sperm is born

Coalescence (合体, Gattai): Black Sperm irreversibly combines his cells to form a more powerful version of himself. The more cells he combines, the stronger and more arrogant the created version of himself will be.

  • Golden Sperm (黄金精子, Ōgon Seishi; Viz: Golden Spermatozoon): A mass fusion consisting of a stated 43 trillion of cells[28], though it's implied to actually be 55 trillion because Atomic Samurai cut off Golden Sperm's right forearm that was said to made of 12 trillion,[29] which he had not recovered or regenerated at the time of the stated former number or when fusing in Platinum Sperm[30] (The form was 9 trillion 999 billion 999 million 999 thousand 999 ones total in the original webcomic[31]). It has a large and extremely muscular physique, displayed with an overpowering golden shine.[32]
  • Platinum Sperm (白金 精子, Puratinamu Seishi): A mass fusion made of a total of 53 trillion 999 billion 999 million 999 thousand 900 cells.[33] It is even shinier than Golden Sperm and has a somewhat slimmer and more agile build.
Warning.png Expand to see original webcomic information. Beware of spoiler content.

Multi-cell Sperm is born

  • Multi-cell Sperm (多細胞精子, Ta Saibō Seishi): A fusion of any number of cells less than ten trillion. The strength of this form has yet to be observed as the only Multi-cell Sperm observed was quickly taken out by Tatsumaki.[34]
Augmented Strength: His strength was presumably augmented, but it was not shown due to Tatsumaki eliminating it instantly.
Augmented Speed and Reflexes: His speed and reflexes were presumably augmented, but they weren't shown due to Tatsumaki eliminating it instantly.
Augmented Durability: His durability was presumably augmented, but it still wasn't enough, as Tatsumaki was able to nearly effortlessly eliminate it.


  • (To Atomic Samurai) "You're looking down on me, aren't you?"[35]
    • "Do you still think you can win? I am a countless number of 'me' merged into one entity. No matter how you cut or tear, how you strike, crush, twist, I'll keep multiplying."[36]
  • (To Genos) "You killed three of me! Looks like you've got some balls. With that, there's only 449,100,712,554 of us left. Heh heh heh. Man, that was some heavy damage, now I'm really in a tough spot, thanks!"[37]
  • "Come on, lets fight. It's gonna be one hell of a satisfaction if I beat up the world's strongest human."[38]
  • "For the birth of one new life, countless others have to be sacrificed. That's why it's precious. That's why it's beautiful. My heart right now is filled with deep sadness. For 53 trillion 999 billion 999 million 999 thousand 900 of me are disappearing into nothingness. On the other hand, I am happy from the depth of my heart. As 54 trillion merge.. the true "me" makes its debut..."[39]


  • Black Sperm cameoed in several volumes before his debut.[40][41]
  • He makes a cameo appearance in Monster of Earth.
  • Although Black Sperm does not combine into Multi-Cell Sperm (多細胞精子, Ta Saibō Seishi) in the manga, he mentions that an incomplete fusion of cells would not be enough to take on the S-Class heroes.[42]
  • Black Sperm's cell count is the subject of speculation. In the original webcomic, when he confronted King, Black Sperm had 11 trillion 449 billion 1 million 712 thousand 554 cells before transforming.[43] In the manga adaptation, Black Sperm has many more cells, using almost 54 trillion cells total by the time he forms Platinum Sperm.[44] In both cases, Black Sperm himself is left with only 100 remaining cells in the aftermath. His total cell count at his introduction cannot be determined, as an unknown number were presumably destroyed during Black Sperm's previous battles with other heroes.
Warning.png Expand to see original webcomic information. Beware of spoiler content.
  • Black Sperm can increase his cell stock by eating protein.[45]


  1. 1.0 1.1 1.2 1.3 1.4 One-Punch Man Manga; Chapter 109
  2. One-Punch Man Webcomic; Chapter 96, page 2-3
  3. One-Punch Man Webcomic; Chapter 109, page 1
  4. One-Punch Man Webcomic; Chapter 94, page 5
  5. One-Punch Man Manga; Chapter 79, page 37
  6. One-Punch Man Manga; Chapter 147 (Online), page 12-13
  7. One-Punch Man Manga; Chapter 150 (Online), page 34
  8. One-Punch Man Manga; Chapter 146 (Online)
  9. One-Punch Man Manga; Chapter 149 (Online), page 27
  10. One-Punch Man Manga; Chapter 150 (Online)
  11. One-Punch Man Manga; Chapter 152 (Online), page 20
  12. One-Punch Man Manga; Chapter 152 (Online), page 35-39
  13. One-Punch Man Manga; Chapter 123 (Online)
  14. One-Punch Man Manga; Chapter 153 (Online), page 26
  15. One-Punch Man Manga; Chapter 141 (Online), page 15
  16. One-Punch Man Manga; Chapter 147 (Online)
  17. One-Punch Man Manga; Chapter 148 (Online), page 24
  18. One-Punch Man Manga; Chapter 150 (Online), page 30-31
  19. One-Punch Man Manga; Chapter 108, page 27-29
  20. One-Punch Man Manga; Chapter 152 (Online), page 34-38
  21. One-Punch Man Manga; Chapter 145 (Online), page 12
  22. One-Punch Man Manga; Chapter 109, page 36
  23. One-Punch Man Manga; Chapter 145 (Online), page 11
  24. One-Punch Man Manga; Chapter 145 (Online), page 17-18
  25. One-Punch Man Manga; Chapter 147 (Online), page 21
  26. One-Punch Man Manga; Chapter 122 (Online), page 10
  27. One-Punch Man Manga; Chapter 146 (Online), page 7
  28. One-Punch Man Manga; Chapter 152 (Online), page 31
  29. One-Punch Man Manga; Chapter 151 (Online), page 13-14
  30. One-Punch Man Manga; Chapter 152 (Online), page 32
  31. One-Punch Man Webcomic; Chapter 80, page 8-9
  32. One-Punch Man Manga; Chapter 148 (Online), page 28-29
  33. One-Punch Man Manga; Chapter 152 (Online), page 38
  34. One-Punch Man Webcomic; Chapter 79, page 9-11
  35. One-Punch Man Manga; Chapter 109, page 24
  36. One-Punch Man Manga; Chapter 109, page 29
  37. One-Punch Man Manga; Chapter 150 (Online), page 34
  38. One-Punch Man Manga; Chapter 151 (Online), page 21
  39. One-Punch Man Manga; Chapter 152 (Online), page 37-39
  40. One-Punch Man Manga; Volume 3
  41. One-Punch Man Manga; Volume 4
  42. One-Punch Man Manga; Chapter 146 (Online), page 8
  43. One-Punch Man Webcomic; Chapter 74, page 8
  44. One-Punch Man Manga; Chapter 152 (Online), page 38-41
  45. Webcomic Chapter 95


Monster Association
Executives Black Sperm *Evil Natural Water *Homeless Emperor Fuhrer Ugly Gums Overgrown RoverNyan Elder Centipede Gouketsu 
Demon Awakened Cockroach Baquma Bug God Building Booper Devil Long Hair Do-S *Eyesight G5 Hundred-Eyes Octopus Vampire (Pureblood) Rafflesidon Royal Ripper Face Ripper Fist Fight Djinn Free Hugger Rhino Wrestler The Three Crows Senior Centipede Showerhead Super Mouse Unihorn The Great Food Tub 
Unknown Gyoffrey Goddess Glasses Venus Mantrap Junior Centipede Haragiri Rosie Choze Benpatsu *Hamukichi *Volten *Evil Eye Gale Hellfire Evil Eggs ManakoPlatinum Sperm Sword Devil Executioner Raptora *Reptera
Mysterious Beings
Dragon (or higher) Boros Orochi *
Demon 170,000-Year-Old Cicada Larva 170,000-Year-Old Cicada Adult Armored GorillaAwakened Cockroach Baquma Beast King Bruinado Bug God Building Booper Deep Sea King Demonic Fan Devil Long Hair *Do-S *Eyesight Face Ripper Fist Fight Djinn Free Hugger G4 G5 Game-Berus Giant Crow Grizzly Nyah Hundred-Eyes Octopus Jumping Spider Macho Daikon Mosquito Girl Rafflesidon Rhino Wrestler Royal Ripper Scaledon Senior Centipede Showerhead Sky King Subterranean King Super Mouse Surprise-Attack Plum The Great Food Tub The Three Crows Unihorn Vampire (Pureblood) 
Wolf Himawari Hotdog Messenger of the Seafolk Piggy Bancon Tongue Stretcher
Less than Wolf
Unknown Alien Seer *Ancient King Angry Grandpa Autumn Phantom Red Golden-ringed Dragonfly *Benpatsu *Choze DarkDark Matter Gunner Eagle Enamel Evil Eggs Evil Eye Evil Natural Water *Falcon Fish of DarknessGale Giant Salamander Gigakigan Goddess Glasses Gyoffrey Hamukichi *Haragiri Hawk Hellfire Junior Centipede Kite Lord Great White ManakoMen's Esthetician Man *Platinum Sperm Rosie Raptora *RepteraSage Centipede Suppon Sword Devil Executioner Venus Mantrap Volten *