He is one of the main antagonists of the Human Monster Saga.
Orochi is a large and ominous-looking monster who is mostly humanoid. He has several large spikes pointing upwards above his head, cracked skin, empty eyes, and multiple sets of pointy teeth inside his mouth. His shoulders, wrists, and fingers have the appearance of monstrous snakeheads with pointy teeth, with the latter ending in large claws. His knees have the appearance of snake skulls and his clothing consisted of a large cape connected to a circular, veiny joint in the center of his chest and a piece of cloth covering his lap. He also has a long, spiky tail.
During his fight with Garou, it is revealed that his body is actually made up of a multitude of smaller, serpent-like dragons, similar to how muscles wrap around the human body. His horns also grew into a crazed head of "hair," more like tentacles. He unravels his body into a mass of writhing dragons, mouths, and claws, and back again, and in this form his cape transformed into a fiery veil around his torso. He appeared to have great control over his shape in that form, taking on a humanoid stance against Garou but climbing up to meet Saitama as a great mass of dragons and fire with no humanoid shape to speak of.
Orochi's heart is an amorphous blob of flesh with eyes.
Orochi is a stern and merciless creature whose immense power is enough to keep in check hundreds of other monsters in the Monster Association. He does not speak much, mostly because he does not need to, since his partner and creator, Psykos, under the guise of Gyoro Gyoro, did all the talking for him. Although Orochi is the leader of the Monster Association, Psykos is the true person in charge, with Orochi acting like more or less an enforcer of her rule. After years of brainwashing him, Psykos has gained almost complete control over Orochi, to the point that he essentially never defy her commands. However, it is still possible for Orochi to ignore Psykos in very rare cases, as he prioritized the threat of Saitama over his creator's calls for help. However, it appears that Orochi has only been using Psykos to promote his own increase of growth through her training and monster sacrifices and has actually been hiding his true power from her, as when Psykos attempts to merge with Orochi, he begins to take control of her and attempts to absorb her in order to increase his own power. Despite this, Psykos manages to regain control over him to an extent, preventing herself from being completely absorbed by Orochi, although he retains a degree of control over this new form, openly stating he would get revenge on Saitama and speaking through Psykos.
Orochi is also much more intelligent than he appears. His laconic nature and beastly appearance caused Garou to underestimate his intelligence, believing him to be a mindless monster when in reality he is described as a "fighting genius" by Psykos. He is also one of the few characters in the series who acknowledged Saitama's immense strength and did not disregard him based on his appearance before fighting him, with the others being Carnage Kabuto and Lord Boros. Additionally, upon sensing the mysterious pressure from him and knowing that he had beaten Overgrown Rover, Orochi quickly realized that Saitama is also the one who not only defeated Gouketsu and Elder Centipede but is the one rumored as the "Monster of the Ghost Town," showing his advanced senses and deductive abilities.
While he may have been a monster, Orochi controls his violent urges and didn't outright kill humans immediately if they caught his interest, such as the case with Gouketsu. This is shown when, instead of finishing him off after defeating him, he captured the martial artist and offered him greater power as a monster in exchange for cooperation. He also grew fond of Gouketsu, often asking Psykos about the executive's current situation, showing that he does prefer some monsters over others. He displayed leniency again with Garou, only asking the recruit to kill one hero to prove himself.
However, he has little to no tolerance for failure from his subordinates, as he ate Awakened Cockroach alive after he failed to kill Genos. On the other hand, he can be convinced to spare subordinates such as Do-S despite their failures, if their usefulness outweighs their failure.
Due to being so powerful and Psykos' brainwashing, his emotions and sense of self are slipping away, very similar to Saitama's problem. Though this is later revealed as a ruse as upon meeting Saitama and being aware of the hero's overwhelming strength, he explained that he only pretended to mindlessly obey Gyoro Gyoro and continued to search for a worthy sacrifice. During the fight with Saitama, Orochi believed that the hero is the "worthy sacrifice" and revealed to him that he had discovered a mysterious ancient tablet in an ancient shrine which depicted him and stated that a worthy sacrifice was needed in order to resurrect a god, leading Orochi to believe that it was referring to his resurrection as a god. Upon his revival, Orochi expressed his desire to get revenge on Saitama, showing he has a sense of pride too.
Having been defeated by Saitama, Orochi also showed distress that the altar he believed dedicated to him was being destroyed and dragged himself to it in an attempt to secure it.
After being reduced to gore by Saitama, Orochi had a very one-track mind as he tried to pull himself back together, haphazardly absorbing any monsters who got in his way. He then attacked Psykos, his own creator, in an attempt to absorb her powers for himself. The two end up sharing one mutated body, with both of their consciousnesses coexisting; this is shown when Saitama punches a portion of his biomass and the shock causes Orochi to momentarily override Psykos again.
According to Psykos, during his past life as a human, Orochi was a broken man who was already losing his humanity by the time she met him. This made him a suitable candidate to be the future Monster King.
Abilities and Powers
Orochi is the leader of the Monster Association, and his powers far exceed that of average Dragon-level monsters. Gouketsu claimed that Orochi is the strongest monster on Earth. Even Bofoi showed signs of vigilance when describing Orochi to Child Emperor. After seeing the damage done to the Metal Knight Drone, Child Emperor admitted that he did not want to fight whoever caused it either. Psykos called Orochi "the ultimate being" and a "success" of her many attempts to break the limit of growth. She is unable to gauge Orochi's power, calling him a "true monster."
Metamorphosis: Orochi's main and most terrifying ability is to change the shape of his body at will. He can shift to and from his humanoid and more monstrous appearances, revealing his "released form" while unraveling his bipedal appearance into a nest of monstrous dragon-like protrusions all along his body. There are nested mouths in place of his face and head while his limbs transformed into dragon-headed coils with their own appendages and extremities. When he wants to fight with his full capabilities, Orochi removes his mask and shifts into his true form. After his body is nearly destroyed by Saitama, he is still able to manipulate and transform the bits of his flesh around the headquarters.
- Elasticity: Orochi is able to stretch and deform his physical shape like taffy whether in his concealed or natural forms. He can stretch his arms a good distance away, and snap it back like a rubber band afterward.
- Shapeshifting: On top of transforming his limbs into dragon-like worms, Orochi can make his coils sheathe and project tooth-like protrusions to act as his fingernails, indicating that he has some form of transformation capacity beyond just mode shifting. He has gotten larger from his initial monster form back when he first became a monster, suggesting some control over his size.
- Tendril Generation: Orochi can unravel his body into a nest of dragon-headed tendrils with their own faces, claws, and fangs that they can use to bite and scratch. After learning an enemy's fighting style, he can also use their skills in conjunction with his serpentine limbs.
- Horn Manipulation: Orochi can extend his horns over long distances. They are incredibly heavy yet able to change and alternate their trajectory very quickly. Bofoi's drone was destroyed by a single strike from his horn.
Monster Cell Generation: While the process has never been shown, Orochi is able to generate Monster Cells with his body. The Monster Cells are harvested from Orochi and then nurtured using a large machine in the Monster Association base. Because he is the source of the cells, he can create as many Mysterious Beings as he wants.
Fire Manipulation: Orochi can breathe fire from his mouth and from all of the dragons over his body. The intensity of his flames prompted Gyoro Gyoro to create a barrier to protect himself, and the flames are ejected from his dragons' mouths so quickly that they appear like beams of glowing energy. The fire is powerful enough to melt and explode the stone environment surrounding him. Had Gyoro Gyoro not protected himself, the fire would have burned him to death. When he transformed during his fight with Saitama, his dragons also changed shape and became completely enveloped in flames.
- Molecular Acceleration: The heat emitted from the Monster King's flames is so intense that anything eviscerated by his dragon fire not only melts into slag. But violently combusts a few seconds after contact with a solid substance.
Absorption: Orochi's body can absorb other organisms that touch him as well as lash out with tentacles to grab at other creatures and pull them into his mass.
- Energy Absorption: Orochi is also capable of pulling up energy directly from the Earth's core. He is seen using this by sticking his tail into the Earth. This ability is so powerful that it creates an earthquake throughout the entire planet and volcanoes all around the planet erupt as the energy from the Earth is being pulled. After gathering enough, he compresses the energy into his body and prepares an extremely powerful attack named Gaia Cannon.
- Regeneration: Using the blood of absorbed creatures, he can regenerate his body from the brink of death. However, he is only shown to be able to regenerate starting from his heart.
- Fusion: If Orochi absorbs an esper of sufficient power, the esper can suppress Orochi's control and take over their fused body, although Orochi still retains a degree of control due to his immense power. This then tremendously amplifies the esper's abilities.
Energy Projection: Orochi has the ability to project large blasts of energy, usually via his dragons. His energy beams are also strong enough to slightly penetrate through Tatsumaki's defenses, slightly tearing and singeing her dress.
- Gaia Cannon (ガイア砲, Gaia-hō) : After pulling up energy directly from the Earth's core via the use of his tail and dragging it up into his body, Orochi unleashes a massive energy beam from his chest in an attempt to obliterate his foes. However; against Saitama, this attack was canceled out by the hero's Serious Squirt Gun.
Immense Strength: While the depths of Orochi's strength have not been shown, Orochi demonstrated amazing physical strength, as evidenced when his horn pierced through one of Bofoi's robots while its arms were raised in defense, going through its entire body with apparent ease and tremendous speed. Given the eerie tone Bofoi spoke in when describing the events, this is no minor feat. He defeated human Gouketsu in combat, and even after Gouketsu became a monster, he deemed Orochi as his superior. During his fight with Garou, Orochi was able to casually restrain him within his hands, and force his way past the Hero Hunter's guard with pure strength, while still holding back.
Immense Speed and Reflexes: Orochi is able to strike Bofoi's robot with his horn so quickly that its self destruction mechanism was broken before it could even activate. Awakened Cockroach was also not able to react to Orochi's attack despite having the sixth sense, although he had previously lost his legs. In his fight with Garou, Orochi was capable of easily following his high-speed movements while the Hero Hunter was in his half-monster state.
Immense Durability: Orochi is shown to receive no damage from his fights against Garou or Gouketsu. After setting his own cloak on fire, Orochi is able to wear the flaming garments for an extended period of time with no apparent difficulty. After his fight with Saitama, he is able to stay alive and remain conscious despite having the majority of his body blown to pieces by him.
Endless Growth: Orochi's voracious appetite contributes to his progression cycle. By eating other Mysterious Beings the Monster King gains both in size and power according to Gyoro Gyoro/Psykos.
Genius Combatant: Similarly to Garou, Orochi is a genius fighter and can instantly learn any move used by his opponents. With just one look, Orochi mastered Water Stream Rock Smashing Fist to the same level as the Hero Hunter.
- Water Stream Rock Smashing Fist (流水岩砕拳, Ryūsui Gansai-ken; Viz: Fist of Flowing Water, Crushed Rock): A highly-advanced martial art invented by Bang that Orochi copied from Garou. He uses this fighting style with his horns and his multiple dragon tendrils as arms against Garou.
- Gouketsu's techniques: While never explicitly displayed as such, Orochi defeated Gouketsu in one-on-one combat prior to the series and took some of his moves for his own.
Fusion with Psykos
Having barely survived his battle with Saitama, Orochi uses his absorption ability to regenerate his body. He absorbs his master Psykos; however, Psykos resists complete assimilation and the two merge into one. During the fusion, they met and received additional power from a being they refer to as God. They are strong enough to injure Tatsumaki and force her to get serious. Their destructive capacity also immensely increases, capable of creating tsunamis over a portion of the planet's hemisphere with a single attack.
- Power Incorporation: Orochi can incorporate other's powers with his assimilation ability. These powers are then increased according to Orochi's own strength. The fusion continuously grows stronger by absorbing the energy from others and the planet through tendrils rooted in the ground; Psykos believes they can become one with the Earth itself as a perfect celestial life form.
- Psychokinesis: Psykos' psychokinesis is greatly amplified by Orochi's power. When their barrier clashes with Tatsumaki's, Tatsumaki is genuinely surprised at how hard it is. They can even usurp Tatsumaki's control of her barrier and turn it inside out, causing Tatsumaki's power to work against her.
- Shapeshifting: This fusion can shapeshift its horns into an enormous avatar of Psykos. The entire body of the fusion can shapeshift drastically into new forms such as jet.
- Tendril Generation: This fusion is able to extend its fingers into large spears.
- Metamorphosis: The dragons which could be created before by Orochi can be created again in greater size and power.
- Energy Projection: This fusion can unleash a widespread energy attack so powerful it can easily cut through the Earth's surface as it passes through, lifting a severed disk of oceanic crust, seawater and the sky above it into the air before it crashes back down. The energy attacks are so powerful that they can easily overwhelm Genos' Thunder Drill Cannon, stated to be capable of destroying a huge meteor in one shot.
- Electricity Manipulation: Through its spears, this fusion can discharge electric shocks powerful enough to temporarily stun Tatsumaki and make her lose control of her powers.
- Regeneration: The fusion retains Orochi's ability to regenerate; after their body was mangled by Tatsumaki, the fusion quickly regenerated from the damage.
- Smoke Manipulation: The fusion is capable of expelling huge quantities of heavy smoke to create a cover for itself and hamper the senses of their opponent.
- Flight: The fusion is capable of flying at high speeds by shapeshifting itself into a jet.
- Existential Pathology: Through their union and subsequent powerup by the God entity, Orochi in his fused form has the potential to corrupt, supplant and assimilate living & non-biological matter through his cellular mass based biology. Enabling the amalgam to spread out and consume the world, becoming a mind capable of giving automation to the whole of the earth, essentially becoming a living planet.
- "Why are there defeated among us?"
- (To Saitama) "I don't know where you crawled in here from, but you are clearly not just some human trash that can be ignored."
- "Powerful... Force... Tatsumaki...Psykos... give me... your blood."
- "You have been tirelessly feeding me sacrifices to promote my growth until now. Thank you, Psykos... Next, it's your turn."
- "The baldy who tore me to pieces is next... I will find him and turn him into a live sacrifice for my resurrection...!"
- ONE told Murata the Monster King is a nurtured/cultivated type of monster. Murata drew a now-rejected sketch on the spot based on what he interpreted that statement as.
- The name "Orochi" (大蛇) literally means "great snake." Yamata no Orochi (八岐大蛇), a legendary serpentine monster/god with eight heads and titanic body who fathered a demon general Shuten-dōji (酒呑童子), is one of the most famous examples.
- Orochi's tail is modeled after a sandworm. Murata went fishing during golden week and got bitten by the worms used as live bait.
- Orochi's "released form" strongly resembles the descriptions of Typhon, a serpentine giant who is one of the largest and most powerful creatures in Greek Mythology. Common or similar characteristics include bodies consisting of a hundred serpents or dragons, unearthly glowing eyes, breathing fierce flames, and fathering numbers of monsters.
- Orochi is the eighth of many "Kings" mentioned in the series and the most powerful of them all, the others being the Subterranean King, the Beast King, the Deep Sea King, the Ancient King, the Sky King, the King of the Underworld (anime-only), the "second Sea King," and the Forest King.
- According to Murata, Orochi is 10 times smaller than Marugori.
- In the original version of Chapter 115, to fight Saitama, he transformed by condensing his body into a more slim and humanoid figure. In this form, his fiery veil increased in size, and the horns upon his head began to glow and even grew dragon heads of their own. His mouth disappeared, his eyes grew in size and become completely white.
- Murata said on stream that Orochi's disaster level is Dragon or above, but did not outright say God. This is similar to the statements made about Boros.
- Murata has stated that if Melzargard, Groribas, and Geryuganshoop work together to fight against Orochi, even with preparation, they have almost no chance of winning.
- However, Murata added right after that "it's still unsure if Tatsumaki can beat Orochi", showing that he was uncertain at the time of the extend of Orochi's power.
- Murata once told the viewers of his live stream that ONE has told him that Orochi would not be one-shotted by Saitama. Murata then added that it should not be a problem for Orochi to survive a few of Saitama's normal punches. This is ultimately proven true when Orochi is revealed to have survived one of Saitama's punches.
- Murata originally speculated that the reason why ONE decided to add Orochi into the story was to give Tatsumaki a big fight in order to injure her, so Psykos disable her later in the story easier. This turned out to be partially true.
- In Murata's original notes, Orochi was first planned to fight eight of the S-Class heroes at once. They would have the advantage at first due to their speed and numbers, but Orochi would then transform into his "released form" and each of the heroes would have to fight one of Orochi's eight dragons. Tatsumaki would then flip the Monster Association headquarters to finish him off, leading into the fight with Psykos and the Monster Association executives on the surface.
- He is the third monster to acknowledge Saitama's power at first glance. However, unlike Carnage Kabuto or Boros, he sees Saitama's god-like power through perception instead of any kind of power-reading ability.
- Orochi is the second monster to stay conscious after being defeated by Saitama and still be able to exchange words, the other being Boros. He was also able to regenerate after being punched, similar to Boros.
- The design of Orochi's form after fusing with Psykos was based on a neuron.
- Murata was uncertain who is stronger between Orochi and Golden Sperm, but stated that Orochi has superior techniques.