Black Sperm

You're looking down on me, aren't you?

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.

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

Appearance
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.

Personality
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, 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. 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.

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. When Golden Sperm is formed, the newly formed sperm copy becomes extremely arrogant, not even caring about his other sperm copies and telling them to simply merge with him due to his superior power.

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.

Gyoro Gyoro believes that if Black Sperm and Homeless Emperor team up together, they can kill anyone.

Sweet Mask stated that even if all of the S-Class heroes fought Golden Sperm, it would still be a very difficult task to defeat him. Along with this, he was the only one besides Saitama who was able to fight against evolved Garou on equal footing, even if it was only for a few moments. It is possible that, in the manga, Golden Sperm is the most powerful member of the Monster Association. Murata does not know who is stronger between Golden Sperm and Orochi in terms of raw strength, although Orochi is a more advanced combatant.

Physical Abilities
Immense Strength: Contrary to his appearance, Black Sperm possesses great strength even with only one individual. A copy of himself was able to significantly injure Atomic Samurai, an S-Class hero, in one hit and was able to subdue the hero with overwhelming numbers of himself in no time during their battle. In his larger state, he was strong enough to embed Genos into the ground with a single strike.

He was also capable of lifting a huge boulder thrown at him by Sweet Mask with ease, as well as tear off one of Genos's arms.

Immense Speed and Reflexes: Black Sperm possesses impressive speed and agility, this was displayed when a copy of himself managed to react to and dodge an air slash from Atomic Samurai, with the swordsman was also somewhat impressed by his speed, saying he was a swift monster.

A smaller, presumably weaker, copy of Black Sperm was able to keep up with Genos' immense speed effortlessly.

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. Regeneration: Black Sperm possesses incredible regenerative abilities, as he was able to fully regenerate his body from being cut to pieces as well as being able to split into copies of himself in the process.

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. He can also split himself at will. However, he is still susceptible to attacks that do not immediately cut him to pieces, such as blunt force or acid attacks.

He has 11 trillion 449 billion 1 million 712 thousand 554 cells.

Fusion: Multiple Black Sperm cells are able to fuse together into one being with greatly enhanced power. However, their fused form loses the ability to separate or regenerate.

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.


 * Sperm Tsunami (精子津波, Seishi Tsunami): Black Sperm rapidly splits up to overwhelm and crush his opponents.

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): A mass fusion consisting of an unknown number of cells. It has a large and extremely muscular physique, displayed with a signature golden shine.


 * Augmented Strength: As Golden Sperm, he was able to physically damage Vomited Fuhrer Ugly, a feat that not even Superalloy Darkshine or Atomic Samurai were capable of with their ultimate attacks.


 * Augmented Speed and Reflexes: Golden Sperm is so fast that he was easily able to punch Fuhrer Ugly faster than the monster could react.


 * Augmented Durability: Golden Sperm has incredible durability, as he remained unfazed when Fuhrer Ugly unleashed a barrage of acidic vomit directly onto his skin, which did no damage whatsoever (where it had previously melted straight through Superalloy Darkshine's skin.)

This state requires at least ten trillion cells to create. With it, he is able to defeat an injured Tatsumaki, as well as temporarily fight with evolved Garou. Sweet Mask went so far as to comment Golden Sperm was beyond his abilities, and that even if all the S-Class heroes ganged up against him, it would be a very difficult fight.


 * Psychic Resistance: Golden Sperm is able to very effectively resist an injured Tatsumaki's psychic attacks with very little effort. However, it has been confirmed that if she were at full power, he could lose.


 * 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.


 * 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.

Quotes

 * "You're looking down on me, aren't you?"
 * "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."


 * "All heroes except Tornado, please form a line and wait for your turn to be killed."

Trivia

 * Black Sperm cameoed in several volumes before his debut.
 * He makes a cameo appearance in Monster of Earth.


 * Black Sperm can increase his cell stock by eating protein.
 * ONE stated that Tatsumaki, in her best shape, could have beaten Golden Sperm.
 * ONE stated that Golden Sperm is equal in strength to Ossan (the main protagonist of Makai no Ossan, another of ONE's works).
 * Murata is uncertain who is stronger between Orochi and Golden Sperm, but states that Orochi has superior techniques.

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