Here you’ll find 25 Mythological creatures that start with O, organized from “Obayifo” to “Ōkami”. They range from spirits and shape-shifters to legendary animals and monstrous hybrids. This list helps writers, game designers, teachers, and researchers find concise reference material.
Mythological creatures that start with O are non-human beings from myths, folklore, and legendary tales worldwide. For example, the West African “Obayifo” is a vampire-like witch that reflects shared beliefs about blood and sorcery.
Below you’ll find the table with Origin, Description, and Famous stories.
Origin: Shows the culture or region where each creature appears, so you can place it in historical or geographic context.
Description: Gives a concise 20–40 word summary of appearance, powers, and behavior to help you compare entries quickly.
Famous stories: Lists one or two named myths or works where the creature appears, useful for follow-up reading.
Mythological creatures that start with O
| Name | Origin | Type | Famous stories |
|---|---|---|---|
| Ogre | European folklore | Monstrous humanoid giant | Puss in Boots, Tom Thumb |
| Oni | Japanese folklore | Demonic ogre or troll | Momotarō, various otogizōshi |
| Ophiotaurus | Greek mythology | Bull-serpent hybrid | Ovid’s Fasti |
| Orthus (Orthrus) | Greek mythology | Two-headed monstrous dog | Hesiod’s Theogony, Labors of Heracles |
| Orobas | European demonology | Demon prince of Hell | Ars Goetia, The Lesser Key of Solomon |
| Ouroboros | Ancient Egyptian / Greek | Symbolic serpent or dragon | Alchemical texts, Gnosticism |
| Oboroten | Slavic folklore | Shapeshifting human or spirit | Various Slavic fairy tales (skazki) |
| Odontotyrannos | Medieval European folklore | Giant horned beast | Alexander Romance |
| Onocentaur | Greek / Medieval folklore | Donkey-human hybrid | Pliny’s Natural History, various bestiaries |
| Oread | Greek mythology | Mountain nymph or spirit | Ovid’s Metamorphoses, The Iliad |
| Oceanid | Greek mythology | Sea nymph or spirit | Hesiod’s Theogony, Prometheus Bound |
| Ōkami | Japanese folklore | Wolf spirit or yōkai | Various regional legends |
| Onikuma | Japanese folklore | Monstrous bear yōkai | Legends from Kiso Valley |
| Onmoraki | Japanese folklore | Bird-like demon spirit | Gazu Hyakki Yagyō by Toriyama Sekien |
| Orang Minyak | Malaysian folklore | Supernatural humanoid creature | Modern urban legends and folklore |
| Orco (Orcus) | Roman / Italian folklore | Underworld deity or giant | Ariosto’s Orlando Furioso, Basile’s Pentamerone |
| Obayifo | West African (Akan) folklore | Vampire-like witch | Traditional Ashanti folklore |
| Ode-it | Iroquois folklore | Undead vampire monster | Traditional oral legends |
| Ohaguro-bettari | Japanese folklore | Female spirit (yōkai) | Various kaidan (ghost stories) |
| Olitiau | Central African folklore | Giant bat-like creature | Accounts from local legend |
| Omukade | Japanese folklore | Gigantic centipede yōkai | My Lord Bag of Rice (Tawara Tōda Monogatari) |
| Ondine (Undine) | European folklore | Elemental water spirit | Paracelsus’s writings, Ondine by Giraudoux |
| Oni-bi | Japanese folklore | Demonic phantom light | Various local legends across Japan |
| Otso | Finnish mythology | Revered bear spirit | Kalevala |
| Ovinnik | Slavic folklore | Spirit of the threshing barn | Various rural folktales |
Descriptions
Ogre
A large, hideous, man-eating monster known for its brutish nature and immense appetite. Ogres often live in castles or caves and are common villains in many European fairy tales.
Oni
Horned, tusked demons often depicted in red, blue, or black. They wield iron clubs and are symbols of evil, punishing the wicked and serving as powerful adversaries in folktales.
Ophiotaurus
A creature with the front of a bull and the rear of a serpent. Its entrails, when burned, were said to grant the power to defeat the gods to whoever made the sacrifice.
Orthus (Orthrus)
A fierce two-headed dog, brother of Cerberus, that guarded the red cattle of the giant Geryon. He was slain by Heracles during the hero’s tenth labor.
Orobas
A demon appearing as a horse that can change into a man. He is said to give true answers about the past, present, and future, and grants dignities and favors to conjurers.
Ouroboros
A serpent eating its own tail, representing the eternal cycle of destruction and rebirth, infinity, and wholeness. It is one of the oldest mystical symbols in the world.
Oboroten
A person who can transform into an animal, most famously a wolf (like a werewolf). The transformation can be either voluntary or the result of a curse.
Odontotyrannos
A massive, one-horned beast said to live near the Ganges River. It was so powerful it could drag away elephants and was encountered by Alexander the Great and his army.
Onocentaur
A creature with the torso and arms of a human joined to the body of a donkey. It was described as having a wild and deceitful nature, blending human reason with animalistic lusts.
Oread
Female spirits of mountains, valleys, and grottoes. They were associated with the goddess Artemis and known for their beauty and connection to the wild, rugged places of nature.
Oceanid
The 3,000 daughters of the Titans Oceanus and Tethys, these nymphs presided over the oceans, rivers, and springs. They were considered protectors of sailors and aquatic life.
Ōkami
A powerful wolf spirit, seen as both a divine messenger and a ferocious predator. Ōkami were believed to understand human speech and could be benevolent or malevolent to travelers.
Onikuma
A giant, demonic bear that walks on its hind legs and preys on livestock and humans. It is known for its immense strength and for having grown to monstrous size from an ordinary bear.
Onmoraki
A grotesque bird-demon formed from the spirits of inadequately mourned corpses. It shrieks with a human-like voice and appears near temples where priests have been neglectful of their duties.
Orang Minyak
Meaning “Oily Man,” this creature is covered in slippery black grease, making it impossible to catch. It is said to use dark magic to abduct young women by night.
Orco (Orcus)
Originally a Roman god of the underworld, the name evolved in folklore to describe a hairy, tusked giant or ogre who feasts on human flesh, living in dark forests or caves.
Obayifo
A type of sorcerer that leaves its body at night to travel as a ball of light. It attacks people, especially children, by sucking their blood or magically blighting crops.
Ode-it
A creature that rises from its grave to hunt at night, seeking to drink the blood of the living. It possessed a magical heart which had to be burned to destroy it permanently.
Ohaguro-bettari
A female ghost who appears as a beautiful woman in a wedding kimono. When approached, she turns to reveal a face with no features except a huge, gaping mouth full of blackened teeth.
Olitiau
A colossal, demon-like bat with a wingspan of over 12 feet. It is described as black, with serrated teeth, and is fiercely aggressive toward humans who venture into its territory.
Omukade
A terrifying, mountain-sized centipede monster so large it could wrap itself around a mountain. It was famously defeated by the hero Tawara Tōda, who shot an arrow into its eye.
Ondine (Undine)
A beautiful female water nymph who could gain a human soul by marrying a mortal man. However, if her husband was unfaithful to her, he was fated to die as a result.
Oni-bi
A type of will-o’-the-wisp, appearing as a floating ball of blue or red fire. It is said to be the soul of a deceased human or animal, now wandering with a grudge.
Otso
The revered spirit of the bear, considered the king of the forest. Not merely an animal, Otso was seen as an intelligent, sacred being and a divine ancestor to humanity in folk poetry.
Ovinnik
A malevolent spirit inhabiting the threshing barn, often appearing as a large black cat with burning eyes. It could burn down the barn if angered, especially on New Year’s Eve.