Kuroi Seishi (黒い精子) is a monster who first appeared during the S-Class Heroes' attack on the Monster Association. Despite his plain appearance and small stature, he is one of the Association's most powerful members and is easily a high-end Dragon level threat capable of defeating even S-Class Heroes. He first appears when Busaiku is separated from Garou, chasing after and tormenting the child. Atomic Samurai steps in, but is soon overwhelmed due to Kuroi Seishi's ability to split into numerous versions of himself, as well as regenerate whenever one of his selfs is killed. When Tatsumaki destroyed the Monster Association HQ, Kuroi Seishi and several other Dragon level monsters emerged from the rubble to attack her. After Psykos temporarily cut off Tatsumaki's psychic power, the monster grabbed her in a giant arm while attempting to crush her. The esper was saved by Genos, though the cyborg immediately had his arms ripped off by Kuroi Seishi and Gums. Once Bang joined the fight and effortlessly killed two of the Monster Association's remaining members before being knocked out by Homeless Emperor, Kuroi Seishi took this opportunity to knock Bomb unconscious.
After King managed to buy some time against the remaining monsters, Tatsumaki began to recover and turn the tide of the battle. In an attempt to defeat her, Kuroi Seishi fused one trillion copies of himself into the much stronger Multicell Seishi, though the newly formed fusion is effortlessly killed by the hero. Sending a thousand copies of himself to perform a kamikaze attack against Tatsumaki and buy about 20 seconds, Kuroi Seishi takes Busaiku hostage, forcing the heroes to simply stand and watch as he fuses 10 trillion of himself into his ultimate form, Ōgon Seishi. This new form proves incredibly dangerous, as Ōgon Seishi takes down Tatsumaki so fast, nobody else could even follow his movement with their eyes. However, this victory proves short lived, as the newly mutated Garou shows up, destroying 99 of the 100 remaining copies of Kuroi Seishi and killing Ōgon Seishi after a brief battle that none of the heroes could even see. Now down to only one life, Kuroi Seishi slips away to watch the battle from afar. The next day, after encountering Saitama, Kuroi Seishi and Overgrown Rover follow him home as pets. The two formerly dangerous monsters are currently entrusted to Butterfly DX and Chain'n'Frog due to Forte losing a bet with Saitama.
Powers and Stats
Tier: At least 7-B | At least 7-A, possibly higher
Name: Kuroi Seishi | Ōgon Seishi
Origin: One Punch Man
Classification: Monster, Dragon level threat, Former member of the Monster Association | Fusion of 10 trillion copies of Kuroi Seishi
Powers and Abilities: Superhuman Physical Characteristics, Shapeshifting, Size shifting, Regeneration (Mid-High as long as he has remaining cell stock), Immortality (Type 3 as long as he has remaining cell stock), Able to make exact copies of himself as long as he has remaining cell stock, Able to permanently fuse copies in order to become stronger | Absorption, Psychic Resistance, though he loses his Regeneration, Immortality, and ability to create copies of himself
Attack Potency: At least City level (A Dragon level threat, considered one of the strongest monsters in the Monster Association. Significantly wounded Atomic Samurai in a single hit) | At least Mountain level, possibly higher (Treated as one of, if not the strongest member of the Monster Association's main forces. Far superior to Kuroi. Sweet Mask said that even with the other S-Classes helping him that fighting Ogon would be no easy task. Casually beat up a highly weakened and depowered Tatsumaki, who in this state could still effortlessly crush Kuroi Seishis)
Speed: At least Massively Hypersonic+ (Able to keep up with numerous powerful heroes) | At least Massively Hypersonic+ (Blitzed Tatsumaki so fast that none of the other heroes could see his attacks while he appeared to simply be walking by)
Lifting Strength: At least Class 100+ (Able to lift hundreds of tons of rubble off of himself) | Unknown, likely far higher
Striking Strength: At least City Class (Wounded Atomic Samurai with a single casual punch) | At least Mountain Class, possibly higher
Durability: At least City level, regeneration makes him incredibly difficult to kill | At least Mountain level, possibly higher
Stamina: Immense | Far higher
Range: Unknown | Unknown
Standard Equipment: None
Intelligence: While he initially appears rather simple and single-minded, he is incredibly combat smart and was one of the few monsters in the Association to use tactics and actually outmaneuver his foes
Weaknesses: If his cell stock gets low, he'll become weaker and eventually be unable to regenerate or make copies | Can no longer regenerate after permanent fusion
- Clones: Kuroi Seishi is composed of over ten trillion copies of himself, essentially allowing him an absurd number of extra lives. He can split into any number of clones that he chooses, as long as he has enough cell stock.
- Regeneration: Kuroi Seishi has the ability to heal any fatal wound to his body by essentially replacing himself with a new copy. He also has the ability to turn any portion of his body into another copy. When Atomic Samurai turned him into mincemeat, Kuroi Seishi regenerated instantly, bursting into even more copies of himself.
- Shapeshifting: Kuroi Seishi has demonstrated the ability to mold his body into whatever he so chooses. Against Atomic Samurai, he turned his body into a giant fist and attempted to smash him. Later, Kuroi Seishi showed the ability to become enormous, as well as elongate his limbs.
- Fusion: In desperate situations, Kuroi Seishi can permanently fuse a large number of copies into a far stronger being. He demonstrated this twice, the first time fusing a trillion copies to create Multicell Seishi, while the second time he fused 10 trillion copies to create Ōgon Seishi. While the former's power is unknown (due to being instantly killed by Tatsumaki), the latter proved incredibly formidable, casually blitzing Tatsumaki and even demonstrating the ability to resist psychic powers (he was unaffected by Tatsumaki trying to snap his neck).
Key: Kuroi Seishi | Ōgon Seishi