How do you make a version of a classic Mamono in a fanmade realm like Oz? Give it a little twist. Ozian Titanias ascend to becoming Wiccen/Witches, Ozian Dragons are incessant buggers (literally), and Ozian Trolls hunt men. Here's an example of a classic Mamono given Ozian distinction, and trust me. She isn't a cherry.
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WATER FEY (OZIAN MERMAID)
Family/Type: Mermaid Family/Fish Type
Habitat: Nonestic Ocean (Surrounds Oz, seperates it from Ev and Ix), Lake Orizon, Mer City
Disposition: Vain, selfish, then aggressive
Diet: Herbivorous; mostly water plant produce
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Fish-type Mamono of the watery regions of Oz. They reside in underwater kingdoms, distancing themselves from Ozian politics. They seldom visit the surface and meet other Mamonos except the Aybee Searpents - teachers of the Merchildren, the Rattlers - proclaimed babysitters - and the aquatic races.
Folklore states the Water Fey are the oldest denizens of Oz predating both fish and mankind. The Mamonos themselves, for that matter, describe humans as 'Water Feys without tails', but they don't usually associate with them. They are also deemed the most beautiful creatures in the world, their fairness a rare gift imparted by the god of love Eros from the beginning of time.
Water Feys radiate the hidden beauty of Oz's waters. They have fair skin unblemished by the world above the waves, silky hair that flows gracefully past their lower halves (like Mermaids, they are fish from the waist down), and a strange abundance of body scales. Some of these scales, smooth as if to blend with skin, run past their barely covered breasts and along their arms and chest areas while the compact ones decorate their tails, reflecting light like natural prisms. They have a pair of extensible wing-fins behind their backs to help them 'glide' as they swim. Plus, they always wear pearls around their neck, wrists and fins. Apart from being a fashion statement, pearls are valued as symbols of the Merpeople, to which they decorate with insignias to state their family prestige.
Water Feys are a far-cry from the normal Mermaid race. They are incredibly high-hatted, self-centered and distrustful towards land-dwellers.They enjoy belittling inhabitants of Oz from the comforts of their watery abode past coral reefs, caring only about themselves. As they bear the title 'most beautiful among the Ozian beings' , they fear their beauty being soiled the minute they make contact with the surface. Towards humans, especially men, they vie them with such repugnance they repell them at first sight, casting their netted veils to throw them back to shore. They refer to them as 'sex-strained land lubbers', refusing to imagine they'd allow human males to bear the inheritors of their race. This isn't the case for humans: laying their eyes on a Water Fey, covered by transparent silked veils trailing behind them like a bridal train, they can't help but think the Mamono are shy of individuals they rarely see.
Due to their complete lack of interest on the affairs of Oz above water, they created self-sustaining empires in the Nonestic Ocean, Lake Orizon and Mer City that are linked to each other by current-travel, covering all aspects of their needs from food (plantations hosting aquatic greenery) to energy (electric jellyfish raised in farms). They attest this is so their race survive on its own - but this doesn't completely block their minds free of what they can't live without. When they lock eyes on a human for the first time, their insides flare as if responding to something they never knew existed within them. Their organs throb heavily, their cheeks begin to flush, they leap in the arms of their fellowmen, sharing sensual kisses in an attempt to experiment an unknown sensation.
The true nature of Water Feys manifest on the seasons of late summer towards winter, when rapidly-changing weather brings in heavy downpours to the states of Zion. Around this time of the year, the Mamonos enter a state of heat wherein their bodies throb in pure longing. DE emitted by their wing fins eat away at their struggling sanity until their selfish disposition is no more. What remains is the heart of a 'man-eater; an aggressive pursuer of man reminiscent of the Mermaid before the current Maou came to power. Their appearances change into a wilder, yet more lascivious spectacle, and they will be truly perverted in nature, outdoing - and even capable of standing toe-to-toe with the ramblings of the Quiberon.
Water Feys in this state scour the territories of their kingdom for a mate, and if they spot a human male, they won't bide their time. Calling at him with haunting voices imbued with charming Daemonergy, they will draw him close to the water's edge, then suddenly cast their netted veils at him. He will be utterly dragged towards to the Water Fey's side. Sometimes, working as a huge group, Water Feys will completely tip boats and ships over, sinking it to unleash its precious cargo of men: a sign of how much they are desperate at this point. By the time a man reaches the Water Fey, the lust-crazed Mamono will push her lips forcibly into his as they both sink to the bottom of the water, filling the depths with ecstatic moans of sex.
A man in the embrace of these Mamonos won't run out of breath underwater. Water Feys have a peculiar ability of covering themselves with a thin layer of air that keeps their bodies and clothes warm and dry, provides air for them to breathe, and protect them from the crushing pressure of the deep. They willingly extend this layer to the person they proclaim as mate for life, so as the two of them will find no inconvenience. Undisturbed by the world, the man will be the only person she will recognize as worshipper of her beauty, and she will adore him as a creature Eros sent to match her. Drowned in pleasure, he will loose the will to fight her off. He will be overcome by lust, and he will desire nothing but her loving body bearing his children.
Similar to the Mermaids of the Mamono Realm, their blood is an elixir of longevity. They can make a mortal's lifespan match that of the Water Feys, so to those they proclaim their husbands, they will let him drink the blood. No one has ever seen Water Fey blood being sold in black markets, but is has been said that a deadly curse awaits those who needlessly consume the blood without their permission.
By the end of the mating season, the Water Fey and her husband disappear from the kingdom. Most probably, to avoid the disagreement of her brethren, she and other married members of her species live in a secluded city where they and their mates can make love, undisturbed. But they're not just nymphomaniacs - Water Feys are highly intellectual and combative, and are experts in underwater homemaking. To support the Mermaid empire, they send their children to live there via ‘mermaid’s purses’ by the time they reach the age of reason, implanting in their consciousness the exact coordinates of their whereabouts. Once the children find their own mates, they will find the city and reunite with their kin, and the cycle continues.
Queen Aquareine, the present leader of the Water Fey, is a benevolent leader who believes the ways of the Water Fey are a thing of the past, though most disagree with her ideals. At present, the King of NeoOz Jeiel Yozama continues to close the gap between the land and water faction of the invisi-state by negotiating with her, and deep in her heart, she wishes both land and water be wed as one kingdom. There are legends that persist that Water Feys can fly, but only she can tell you that truth for sure.
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NOTE: The Water Feys are based on the 'black side' of mermaids according to myth, wherein they are assumed as man-hunters. Yeah... reminds me of Pirate of The Carribean on the mermaid scene. BRR! Gives me the chills. But since they have you in sight, you're in for a mire. Let's say it's up to you how you'd discipline such a sex maniac. Bye-ho!