One of the strongest upper moon demons, Gyokko appears in the new Swordsmith Village arc in the Demon Slayer series to destroy the swordsmith village, an important sanctuary for the demon slayers.
Gyokko is a grotesque demon with mouths for eyes and an eye on his forehead as well as his mouth, his genie like body that comes out of vase sprouts multiple child like arms making him an even more grotesque demon to look at. Before Gyokko became a human, he went by the name of Managi, a person with a disturbing and evil past but was resurrected by Muzan and reached upper moon 5 status by doing Muzan's bidding.
Upper Rank 5
Gyokko is a gruesome demon with no remorse for human life, during the swordsmith village arc, his first appearance happens when a village swordsmith stumbles upon one of the vases that Gyokko hides in, the unsuspecting victim is then sucked in and devoured after which Gyokko emerges out of the vase. The upper rank 5 demon, Gyokko is an extremely sadistic demon and takes great pride in his grotesque art. It is usually dismembered bodies of his victims joined together and is seen when Gyokko gleefully displays the stitched-up corpses of swordsmiths with swords stuck into them to Muichiro.
He also goes in great detail when explaining his art and takes great pleasure in the pain endured by his victims, this is also seen when he twists the swords causing the barely alive swordsmith excruciating pain.Gyokko is willing to go the extent to please his master, Muzan, even when he is not too happy with what he is ordered to do. Gyokko is also seen to be short-tempered and is easily enraged, especially if someone were to make fun of his so-called art, he also possesses a narcissistic personality and always praised himself stating that his art was always beautiful and was very easily antagonized when Muichiro insulted his art causing Gyokko to lash out.
Blood Demon Art Technique
Gyokko's blood demon art is a unique technique that allows him to manipulate his own flesh, he is able to turn his hands into pots that can either unleash powerful attacks or morbid aquatic creatures. It is said that Gyutaro and Daki (former upper moon 6) have killed a total of 22 Hashiras, for Gyokko to reach upper moon 5 it would have taken him even more kills to achieve that rank. However, Gyokko also has a true form, which is unleashed during the heat of a battle, a humanoid body covered in scales, a kind of half-reptile, half-human form, similar to a merman. Just like his peers, Gyokko also has incredible durability which makes decapitating him nearly impossible, especially when he is in his humanoid form as his scales are able to harden making his body very difficult to cut. As an upper-rank demon, Gyokko also has quick regenerating abilities along with intense speed and reflexes. He was able to keep up with Muichiro's attacks for a long period of time and managed to evade all of his attacks. Once Gyokko transforms into his true form, his abilities are enhanced, and he is able to move at amazing speeds while enabling him to turn anything he touched into grotesque fishes. Resilience and stamina is also something that made Gyokko an extremely powerful demon and thanks to his blood demon art he was able to become even stronger.
Gyokko's is also able to transport from one vase to another while also creating multiple vases in the area to teleport to, confusing his opponent and evading attack, this is what makes his blood demon art unique, he is also able to spawn numerous amounts of grotesque looking fish that were used to attack the swordsmith villagers. These weird fish-like creatures varied in size and some had human-like legs and arms while also sprouting fangs. However, these creatures were used mostly as a distraction and posed no real threat if a Hashira was nearby.
Gyokko's body manipulations allowed him to transform one of his many arms into pots that unleashed floating fish that shoots multiple poisonous needles for their mouths at opponents. Another sublime attack is when Gyokko shoots water from the pots that captures and drowns the victim making it hard for them to breathe or escape the water prison.Most of Gyokko's attacks bare strong resemblance to aquatic abilities and is a powerful technique which can be used to mercilessly kill his opponents. A fun fact about Gyokko, is that he loves to create and paint his vases, which Muzan sells for exorbitant prices claiming that the vases were made by a talented artist. Regardless, Gyokko is seen to be one of the most powerful demons in the Demon Slayer series and is a very difficult demon to defeat.