transformation
Eerie x Reader x Caspian
Your siren mates guide you through the transformation process; your change from human to mer, and you finally realise what they are to you.
The cove does not welcome the light.
It swallows it instead, dragging the last traces of dusk beneath the surface until everything becomes dim, green, and shifting. The water there is too still, too deep for something so close to shore. Even the waves seem reluctant to enter.
You lie half-submerged where the tide laps at the rocks, eyes screwed shut, your body no longer entirely your own.
Your hair moves before you do, long strands of it spreading like ink in the water. Your chest rises, slow, uncertain.
The change takes you only hours, but they knows the truth of it: the body transforms quickly; the mind lags behind, tangled in memories of air and gravity and breath that burns.
“Don’t rush it,” You hear one of them, Caspian, you think, say softly.
His voice carries the way all siren voices do, less sound, more feeling. It curls through the water and brushes against you like a current.
“It’s wrong,” you rasp, fingers clawing at the stone. “Something’s wrong…”
Caspian moves closer, slow enough not to startle you. Male sirens are larger, built for endurance and distance, not the delicate lure of their female counterparts. His presence can be overwhelming if he isn’t careful.
A hand closes around your wrist.
Firm. Unyielding.
“You’re fighting it,” he says.
His grip keeps you anchored when your body tries to twist away from itself.
“Don’t.”
Another presence circles behind you.
You don’t hear him approach. You feel him.
A brush of movement. A shift in the current.
Then, fingers, lighter, trailing along your spine where the change burns brightest.
Eerie murmurs, his voice softer, but edged with something sharper.
“The body breaks before it becomes.”
Your eyes snap open.
For a moment, they are human, wide, searching, confused. Then the shift comes. The pupils stretch, the colour deepens, and something ancient flickers behind them.
You inhale sharply and panic.
Your hands fly to your throat, your body jerking upward as if trying to breach a surface that is no longer necessary.
“It’s all right,” Caspain murmurs, closing the distance now. “You don’t need air anymore.”
You don’t understand the words. Not yet. Their language still a stranger to you. But you understand the tone. Fear meets calm, and for a heartbeat, they hold you against each other.
Then you thrash.
They expect it.
Eerie pulls you into his arms, wrapping around you from behind, anchoring you against his chest, letting you feel something steady, something unyielding but not cruel.
You fight him at first. Of course you do.
But then, your movements falter.
The ocean is patient. It teaches quickly.
Your lungs don’t burn. Your chest doesn’t tighten. There is no suffocation waiting for you, no desperate need to reach a surface that has already lost its meaning.
Your panic has nowhere to go.
It unravels.
Slowly, you still in his arms.
“That’s it,” he says, softer now. “You’re safe.”
Safe.
Even the tide seems to hush at that as it slips between the rocks, dark water folding in on itself like something alive, something listening. The surface barely stirs, but beneath it, everything shifts.
You tremble between them.
“It hurts…” Your voice breaks into a thin, panicked breath. “Please, I can’t,”
“You can.”
They hold you firmly between them. Eerie’s arms braced around your shoulders and waist, Caspian locking your hands gently but securely so you can’t thrash against the stone. Their presence is solid, immovable, the kind that does not break, not even by the sea.
Their voice follows that same pattern. Calm. Certain.
The pain surges again, violent this time.
Your legs jerk, muscles seizing as the bones beneath begin to fuse and reshape. The sound, faint, internal, wrong, makes you choke on a sob.
“Please… make it stop,”
“You know we can’t,”
Another hand comes up to your shoulder, pressing you down gently as the water rises around you. Not forcing, guiding.
Holding.
Behind you, Eerie leans closer.
You feel his breath near your ear, cool, almost curious.
“You’re almost through it.”
“I’m not,” you gasp, body arching as the change tears through you again. “It’s getting worse.”
A second pair of hands slides over you, slower.
Reverent.
From behind, Eerie traces the line of your spine as it shudders, fingers lingering where the transformation hurts the most. There is a strange care in it, too attentive, too precise.
Caspian’s grip tightens again, not to hurt, but to steady you as your body convulses again, your legs pulling together, the last remnants of what you have been dissolving beneath glistening scales.
Your body lurches again, and this time you scream, raw and broken as your legs seal together completely, scales blooming across your skin in a ripple of dark, glistening colour.
Caspian moves instantly.
He pulls you against him, not roughly, but with undeniable strength, one arm bracing your back while the other holds your wrists still as they tremble and claw.
“Look at me.”
You can’t.
“I said, look at me.”
There is no anger in his voice. That makes it worse.
You force your eyes up.
“Breathe,” he says.
Behind you, Eerie’s hands slide along your sides, slow and deliberate, feeling the transformation as it settles, as if studying it.
“See?” Caspian murmurs. “It’s almost over.”
You shake your head weakly. “It doesn’t feel like it…”
They whisper to you, cutting you off, their voices overlapping around you, not raised, but threaded with something tight beneath the surface.
Possessive. Concerned. Shared.
Another wave of pain rips through you and ends the exchange entirely. You cry out, body curling inward, but you can’t escape it, can’t escape them.
They won’t let you.
“Look at me,” Caspian says again, firmer now.
You shake your head weakly, tears slipping into the water.
A hand, cool, careful, tilts your chin up.
Not his.
Eerie has moved closer again, just enough that you can feel him beside you now, not behind.
“Look,” he coaxes softly.
Between them. At them.
Your gaze lifts, unfocused at first, then catches.
They are both watching you.
Too closely.
Not just concern. Not just care.
Something deeper. Hungrier.
“You’re ours,” Eerie murmurs, almost gently. “Our pearl. You should see the moment you become it.”
Your breath hitches.
Caspian’s arm shifts around you, pulling you tighter against him as the final change begins, slower this time, but deeper.
Your body lengthens, reshapes, and your tail forms fully beneath the surface in a powerful, fluid line.
You gasp, not from pain this time, but from the overwhelming wrongness of it.
Another wave hits.
But this time, it doesn’t tear through you.
It settles.
The pain dulls, draining out of you like ink into the sea, leaving behind something heavy. Strange. New.
Your body floats differently now.
Not resisting.
Belonging.
You go still in Caspian’s arms, your breathing uneven but slowing.
“I can’t feel my legs,” you whisper.
“You don’t have them anymore,” he says lightly.
Caspian adjusts his hold, more careful now, one hand supporting you as the water carries more of your weight.
His hand moves from your wrist to your back, broad palm pressing steadily and warm as if he can hold you together through sheer will.
Eerie’s fingers slide down along your new form again, less curious now, more certain.
Claiming.
“You feel that?” he asks softly.
You do.
The water holds you differently now. It doesn’t press, it welcomes. Your body responds without asking your permission, shifting, adjusting, belonging in a way that makes your chest tighten with something dangerously close to relief.
“…yes,” you whisper.
“There it is,” he says.
They both exhale, something easing in their posture for the first time.
“She’s through it.”
“Of course she is,” Caspian says, the eccentric gleam returning in his tone.
“Try moving,” he says.
You hesitate.
Behind you, Eerie’s hand slides down, guiding, not asking, until it rests along the length of your newly formed tail.
“Like this,” he murmurs.
He moves it slightly.
Your body follows.
You gasp.
The motion is smooth.
Effortless.
Wrong, but right in a way that makes your chest tighten.
“There,” he says quietly. “You feel it.”
You nod faintly, eyes wide.
His grip lingers a moment longer than necessary before releasing, drifting back into the darker water behind you.
Watching. Waiting.
Caspian loosens his hold, giving you space while staying close enough to catch you again if fear returns.
You don’t bolt this time.
Instead, you look at your hands.
Webbing stretches between your fingers, delicate and translucent. You flex them, watching how the water moves differently around you now. Your tail flicks, tentative, curious.
Confusion replaces terror.
Better.
Caspian reaches out, slowly, letting you see the movement before he makes contact. His fingers brush yours, guiding your hand through the water.
You swallow hard. “I don’t… feel like me.”
Eerie’s hands return, and he doesn’t let go.
“You are.” he says.
Caspian tilts his head, voice threading through the water again.
“Just different.”
Silence folds in around them.
The cove, the dark water, the slow pull of the tide, it all feels closer now. Like it is listening.
Your fingers twitch, but they are still holding you, one solid and grounding, the other light but ever-present, never quite letting you drift too far.
Suddenly, your eyes widen.
A new feeling.
A different kind of breath catches in your chest, something closer to wonder.
They feel a faint pull then.
Not physical.
Something deeper.
The bond.
It forms the moment you change, a tether between the three of you, quiet but undeniable.
They felt it before you even opened your eyes, a sudden awareness, like a third heartbeat that wasn’t their own.
Now you feel it too.
Your gaze snaps to theirs.
There it is, recognition without understanding.
They give you a small, reassuring smile.
“I know,” Eerie says. “It’s strange.”
You drift closer this time, not out of fear, but curiosity. The space between them shrinks until their foreheads nearly touch yours.
The bond pulses.
A flicker of sensation passes between them, Eerie’s calm, Caspian’s excitement, your uncertainty, shared in a way that has nothing to do with words.
Your expression softens.
Not fully. Not completely.
But enough.
The tide begins to pull you inward, then, deeper into the cove where the light doesn’t reach at all. The water closes over you slowly, like a curtain.
You tense, but neither of them lets go.
“Easy,” Eerie murmurs.
“Let it take you,” Caspian adds.
Between them, held on both sides, you let the water carry you.
And this time, you don’t fight it.
Behind you, their voices drop low, just beneath the surface, meant for each other now.
“She’ll adjust quickly.”
“She has to.”
There’s a pause.
Then, quieter still, “She’s perfect like this.”
There’s a soft hum of agreement.
“Better.”
Their hands never leave you as they thread their fingers through each other's, disappearing fully into the dark.
And though the pain is gone, replaced by the slow, strange rhythm of the sea inside you, their hold doesn’t loosen.
If anything,
It settles.
xoxo aurelie
© aureliexo