Ariel just wanted to be human. That was her one and only wish, her dream, her passion. To walk on land with a prince she was smitten with, to hear the bustle of the land-cities and to dance around on her very own feet.
But NO. The sea-witch Ursula had tricked her. After she had been forced back into the sea, she'd lost all hope, her heart shattered by the immense sense of loss and pain and rage and sorrow. She even half expected to die from the crush of emotion…
Then Ursula, in a flicker of odd kindness, turned her free from her cage one day, saying, "No, my dear fishy. I think I'll put you to good use…"
And so it had begun. It started with the small things, cleaning out the witch's cauldron, sorting her jars and canisters on the coral shelves, scraping the moss out off the cave floor. Ursula had entertained the notion of taking Ariel's voice again, to keep her from calling for help, but after the young mermaid had been silent for so long on her own accord, the sea-witch decided against it. There was no one around to hear her anyways.
After nearly a year of doing the witch's bidding, Ariel began to learn from her captor, who taught her little spells for killing the stray hermit crabs and krill that sometimes wandered into the cave. Little by little, the bitterness in the fire-haired mermaid's mind and soul began to grow, swallowing up her kinder traits. Soon it became easy to kill the intruders, and she even went out of her way to scour the limits of her new home, searching for victims to torture and kill.
Her new attitude pleased the sea-witch, and barely three years after she was dragged to the cave, Ariel was taken under the sea-witch's tentacles and taught the ways of witchcraft and dark magics.
She was an excellent pupil, practicing her newfound power until she was every bit as powerful as Ursula, and soon she surpassed her mentor. She sacrificed her left hand in a ritual to double the expanse of her might, and in a cruel twist of irony, she replaced it with a trident-like fork, the points filed to razor points and the prongs serrated. Ariel was a sea-witch now, the pallid gray tone of her skin, her barracuda teeth, and her tangled mass of long blood-red hair attesting to her transformation.
Atlantis was mourning. It was the fifth year since their youngest princess had been stolen, and they had stopped all activities to spend the day remembering. King Triton was the most deeply affected, and he had only just managed to pull himself out of his seashell bed and eat something that morning. He sat in his throne, head hung and face buried behind his hand, the other gripping his trident so tightly that his callused knuckles had turned white. He was concentrating so hard on holding back the tears that stung his eyes, on swallowing back the sour bile in his throat, that he never noticed a dark shape slipping into the room from behind.
Ariel was not dead and gone, like all the Atlantians had thought, but was very much alive. Her forked left hand glinted in the dim glowfish lamplight, and she glided forward silently until she was mere inches from the throne. A flicker of the old, kind Ariel broke through the insanity that now twisted her mind… Then she murdered it as efficiently as she'd murdered the royal guards. It had been so easy, slitting their throats and swimming past while they bled into the water. Already the tiger sharks and hammerheads had started their charge, following the smell of sweet mer-blood and tearing the half-dead guards into bits with their teeth.
Ariel rose a bit over the throne back, her ragged tailfin making gentle swishing sounds as she did, until she could lean over and kiss the top of his head. Triton's entire body jerked as if stung by a jellyfish, then his wide-eyed gaze lifted up, head moving back and back until he saw the tattered, twisted face of his lost daughter. Before any words could be said, there was a tug around his exposed throat, and a cloud of dark red filtered through the water, filling the space before him.
The merwoman laughed when he realized he was dying… She always did, and she held a perverse joy at the way he stared uncomprehendingly at her jagged fangs, at her missing left hand that had been replaced by the forked weapon, then the blood left his face and the light in his eyes died, and the mer-king floated up, out of his throne, floating to the ceiling like a dead fish.
That's exactly what he is now. A dead fish. The she was gone, nothing more than a shadow in the water, and the sharks followed the blood smell. They stared at the dead king, then with a flick of their tails, the sharks charged.