It wasn't uncommon to hear of a mermaid falling for a human. A lucky few were able to find a way to be with their loves, though far more stories ended in tragedy.
But a merman? They were rarely known for even coming to the surface, let alone interacting with its inhabitants.
It happened once, though. A merman with dark hair and eyes the colour of the ocean caught sight of a woman who also had the sea in her eyes, and it was love at first sight.
He made a deal with a sea witch, who granted him the ability to walk on land...but only for 15 years. He intended to make the most of them though, and immediately found the woman and asked for her hand.
They lived in bliss, and welcomed two sons into the world who also had the ocean in their eyes. Their seaside home was full of love and happiness.
All too soon, though, the 15 years were up, and the merman was called back to the sea. He begged the witch to give him more time with his family. She heard his pleas and presented him a knife; if he could kill his wife, he could stay with his sons. Otherwise, he would perish.
With a heavy heart, he went home to spend his final evening with his family. Once the morning arrived, he disappeared into the sea, never to be seen or heard from again, leaving his wife and sons heartbroken.
The sea witch, in disguise, told the family that he was a fugitive and ran away to escape the law. The family never learned of his deal, his fate...or even his past.
"Have a nice swim, Captain."
The sea witch's words jarred him from unconsciousness, but they were the last thing he heard before he felt the cold smack of the water.
And it hurt. Bloody hell, did it hurt. He must have landed feet-first, because he felt the full sting of the impact in his legs.
What a cruel irony, he thought; I've spent my whole life surviving on the sea, and the sea is where I shall perish. It was probably a fitting end for the pirate captain, but Killian had so much he wanted to live for now.
He wanted to fight the water that was slowly encroaching on his lungs, burning, but the pain in his lower half was too much to bear. So he slowly sunk down into the grey depths of the harbor, waiting for Davy Jones to claim him.
He conjured the image of Emma in his mind, hoping beyond hope that he could spend his last moments thinking on the woman who had become his light. He'd never be able to tell her just how much she meant to him, but maybe if he focused on her, it would ease the pain of dying.
Slowly, the agony in his legs went away, and the burning in his lungs ceased. This is it. I love you, Emma.
Until he realized he was breathing.
Underwater.
He opened his eyes—he hadn't even realized he was squinting them shut—and tried to take stock of the situation.
He was not only breathing, but it felt like he was standing, even though he was clearly floating. It should have been impossible, but it somehow felt completely normal.
He could only think of a few creatures he'd encountered that could accomplish the feat he was pulling off now. Tentatively, he glanced down.
He still wore his leather jacket, vest, and button-up shirt, and his hook and brace were still attached to his left arm.
But where his legs should have been was a tail. A bloody tail?
It looked exactly the same as the lower half of any mermaid he'd ever encountered: long, tapered, covered in scales, and ending in a fish-like, two-pronged fin. This one in particular was golden in colour, with bright blue undertones; despite his shock at seeing it, Killian was rather impressed.
But admiration quickly turned to anger. Had he been cursed? Given his history with Ursula, he wouldn't put it past her, though he couldn't fathom why she'd condemn him to this rather than outright kill him.
He needed to find Swan. But first, he needed to reach the surface.
Cautiously, he tried to move his new appendage. Just a quick flip back of his fin shot him straight up, much faster than he anticipated.
"Bloody hell!" he exclaimed, bubbles escaping his mouth. He clamped his hand over his mouth in shock that he was able to speak, but that movement made it apparent that while pirates and leather mixed very well, there was a reason you never saw a merman in a coat: clothes were awfully cumbersome under water. As long as he was water-bound, he'd have to ditch the coat, and then some.
Moving his tail much slower this time (in part to get used to the motion), he made his way to the surface, working his jacket off at the same time. He was worried he'd be cold in the frigid Maine water without it, but it didn't seem to affect him.
It didn't take long to break through, and he carefully used his arms to help him tread water as he scanned the scene to get his bearings. He was still near the Jolly Roger (his Jolly Roger, gods be good), but Ursula was nowhere to be seen.
He briefly contemplated trying to climb up to the deck of the ship, but with only one hand and no legs, that seemed too daunting a task to attempt. So he instead made his way over to a little-used dock and pulled himself up to take a seat, brushing his hair out of his eyes as he settled. Out of the water, his tail seemed to shine even brighter, despite the overcast, sunless sky. At least I'm still devilishly handsome, he smirked to himself, albeit halfheartedly.
He then remembered that he had once seen a mermaid gain human legs simply by smacking her tail against the ground, so he decided to give it a shot. Twisting so his body was parallel with the edges of the dock, he lifted his fin and smacked it down as hard as he could. The deck rattled and a jolt of pain ran all the way up through his spine...but no change. He tried a few more times, but the result was the same. He lied back and sighed in defeat. Now what?
The talking phone! He sat straight up when he remembered he had the device in his jacket. He frantically rummaged through the very wet pockets until he found it. Wiping off the excess, water, he began pressing the button combination he had memorized to dial Emma. But nothing happened; nothing was on the screen, and no amount of pressure on the keys elicited a response. Dammit; the plunge must have disabled it. Wonderful.
Alright, I'll have to search for help via water. Odd that for so long, he felt most at home at sea, yet now the thought was somewhat terrifying. (You know your home isn't on the water anymore, mate, he told himself.)
He deftly worked open the buttons on his vest and shirt with his right hand, then stripped off the wet materials—he wasn't going to let those clingy shirts slow him down. Again, he braced himself for the chill that was sure to hit his now-bare chest, but it never came. I guess that's one perk. Out of habit, he carefully folded his clothes and set them in a neat pile on the dock. Glancing at his hook, he thought about taking the brace off, lest it too weigh him down, but decided to leave it on. He didn't need to be down any more appendages.
He swung his tail out so it hung over the edge of dock, and gripped the edge, preparing to dive in. Before he did, he caught a glance at his reflection in the water. The blue highlights in his fin matched his eyes perfectly, and the gold was a seemingly natural complement to his skin tone. His dark hair hung wet against his forehead, save for where he'd pushed it back. Now that he'd ditched his clothes, the muscles in his chest and arms were on full display. And he smiled to see that his tattoos were still in place.
He was a perfect merman specimen. Almost as if...almost as if I was born to be one.
He shook his head, as if to get rid of that thought. Time to find Swan. He took a deep breath (out of habit, he supposed), hunched back to prep, and then launched his lean form into the murky water.
"Is it done?"
"I threw him in the harbor and he never surfaced. So I'd say so."
"Excellent work, Ursula. Let's continue, shall we?"
The Dark One was quickly enveloped in a deep purple smoke, which dissipated as fast as it appeared, revealing Killian's form in his place.
"You're getting too good at that, Rumple."
"I know, love," he responded in Killian's voice.