Disclaimer: I do not own Glee or any of its characters; Ryan Murphy and Co. hold that honor. I'm simply writing this for fun, not profit.

The mermaids of the Great Lake were a mystery to Kurt.

Kurt had only caught a glimpse of one on a cool autumn morning while he was strolling across the grounds. It had been carrying a writhing creature the size of a groundhog off, bobbing along the surface of the lake before vanishing underneath with a sharp smack of its tail. Shuddering, he had quickened his step and opted to spend his free time in one of the courtyards instead, determinedly putting the mermaid sighting out of mind.

He hadn't thought about them again until winter was fully upon them, his gaze occasionally drawn to the lake as it slowly yet inexorably froze over. Cozily bound up in his robes and scarf by a fire, he gazed out the frosted window and wondered how the mermaids and other creatures that inhabited the lake faired once the temperatures fell.

"They're hardier than they look," was the elusive and singularly unhelpful answer that his Magical Creatures professor was able to provide when Kurt pressed him for answers. "Some pass, naturally, but for the most part they're quite hardy."

Winter brought its own challenges for Kurt, including midterm exams, and he chose to focus on those tasks rather than the enigmatic plight of the creatures dwelling in the frozen lake. It was the day before he returned home for Christmas break that he spared them another thought, gaze drawn to the lake as snow continued to pile on top of the ice. He halfheartedly debated asking a professor whether or not the mermaids celebrated any sort of holidays or had indeed any conception of the passage of time in minute figures such as days or weeks or months before tossing the notion aside. It was useless to express an interest in creatures so singularly unpleasant; simply put, aside from Kurt himself, no one cared.

Returning to Hogwarts after Christmas and New Year's had been a refreshing way to clear his mind. He loved visiting his family, loved his dad and stepmom and stepbrother, but he also loved Hogwarts and all it had to offer, and being away for so long felt like surrendering the use of an extremity. Being able to tread over the snow-covered grounds and sweep down hidden corridors and endless hallways was a delight that Kurt was sure he would never tire of.

What he loved most was exploring the castle once the younger students were safely abed and the older students were engaged in their own tasks. The Invisibility Cloak that his mother had given him was invaluable on his nightly escapades, providing him the perfect cover to slip into closed libraries unseen or raid the kitchens for a midnight snack. Once, when he was feeling particularly mischievous, he had raided Professor Cabot's private stash of potions, tenderly handling the vials that continued ingredients so dangerous that the warning labels had simply shown Dire need only.

He'd always been comfortable around Potions – something about the mechanization of the process, the tinkering and toil involved, reminded him of home in a way that Herbology and Charms simply did not – and he hadn't taken anything from the stock, gazing admiringly at the collection for hours before finally – reluctantly – departing.

He hadn't known that such extensive knowledge would come in handy until the ice had thawed completely. Robes dancing around his heels as he walked briskly down the stairwell, cautious of being caught, he'd stilled when he heard it: a thin, wailing noise, coming from the lake.

Heart racing, every muscle frozen in place, he'd waited in for several long moments in silence before it came again, gasping pants so sharp and thin that they seemed to scrape along his skin as they drifted towards him.

Without wasting a moment – and, indeed, before he could question the sanity of the decision – he bolted across the grass to the lake, drawn by some invisible force towards the noise. He had almost convinced himself that he was entirely out of his mind when he heard it again, steadier but fainter, close but unseen. Treading cautiously – wary of anything that might do him harm – he made his way towards a heavily shadowed figure as it lay prone half-out of the water, tail writhing weakly under the surface.

The first things he noticed were the rounded barbs sticking out of its tail – the next, the soft, masculine curves of the mermaid's – merman's – jaw. Pupils blown and serrated teeth bared in a pained snarl, the creature looked barely human. Mesmerized by the display – and horrified at the amount of blood discoloring the surrounding water – Kurt approached on feather-light footsteps, freezing when a leaf crunched underneath him.

That got the merman's attention. Suddenly the wet grass that he had been directing all of his attention to was inconsequential. He looked up at Kurt and bared his teeth in a warning snarl, his arms still trembling underneath him as he struggled upright, attempting to slip back into the water. His tail lashed as he struggled, unable to get his bearings even as Kurt watched, vaguely curious and horrified.

Every instinct warned him to walk away, to leave the merman alone to nurse his wounds, but he couldn't tear his gaze from the merman's curved shoulders, his floppy curls, his pointed ears. Had he not possessed a tail and a truly abominable temper, then Kurt might have even wagered that he seemed vaguely human.

But, despite the name, mermaids were creatures that needed to be treated with the same level of respect and wariness as Hippogriffs. Interaction was strongly discouraged, for obvious reasons: even a level-headed, uninjured mermaid was likely to swipe at a student that dared to come too close. The wounds would not be fatal, but excruciating reminders that mermaids possessed things no human would ever desire to encounter.

So it made no sense, logically, for him to step closer, falling into a crouch naturally once they were close enough to touch.

Eyes closed, the merman was strewn across the muddy grass with his cheek pressed against it, untrimmed nails scrabbling weakly at the grass as his tail thrashed and thrashed and thrashed, trying in vain to dislodge the barbs attached to it. Kurt watched, fascinated, as he reached down with clumsy fingers to try and pluck them out that way, unable to get the right grip with the barbs embedded as they were.

Letting out a sympathetic noise, Kurt flinched when the merman's head whipped up to look at him, a mixture of wariness and anger lurking underneath the surface.

Kurt knew that the anger wasn't directed at him, but he still stepped back, giving the merman more room until he was slowly backing away. The merman resolutely ignored him as he did so, thrashing his tail until Kurt was a dozen, two dozen yards away. He burst into a run once the merman was just under the crest of the first hall, heading pell-mell over the grounds towards the castle.

He found what he needed and returned to the lake before ten minutes had passed, the merman still prone against the grass as he let out another warbled cry, high-pitched and heartbreaking. Kurt didn't care if he wasn't human, didn't care if he couldn't comprehend human emotions in the same way: he needed to help because he was human and no creature deserved to suffer so needlessly.

When he approached a second time, the merman didn't flinch or writhe away, didn't bare his teeth and snarl up at him. His shoulders bunched and his fingers tensed in the grass, tail lashing once in warning, but he didn't move, otherwise, remaining very still and alert, almost human. Kurt edged closer, offering the three vials first as a sort of peace offering even though the merman's eyes were averted. They flickered up to the vials with interest, bright gold and unflinching. Kurt couldn't help but stare, forgetting his task entirely until the merman looked away, tail lashing the water once more. The bleeding had slowed to a crawl, although Kurt still didn't like the blotchy paleness of his skin.

Inching close enough to reach out, heart pounding in his chest, Kurt eased himself onto the grass, careless of the moisture soaking into his clothes, and held out the first unstopped vial.

The merman didn't take it for several long, tense moments. In the silence Kurt wondered, not improbably, if he was about to be bitten or scratched and sent hobbling off to Madame Astor's for a hasty antidote. Just when he was about to set the vial on the grass and leave the merman to his own devices, Kurt froze when the merman shifted partially upright, balancing on an arm as he reached clumsily for the vial.

He downed it in a single grimace-laden swallow. Kurt arched an eyebrow, impressed at his tolerance – most students vomited from the mere smell of the potion – before the merman twisted onto his side and retched, emptying the contents of his stomach onto the grass.

He heaved for so long that Kurt worried that he had given him too strong a dose, that mermaids were somehow dangerously susceptible to the poison-purging potion that he'd given him, when, with a full-body shudder, the merman vomited a mouthful of black bile. Relaxing slightly even as his heart continued to twist in his chest – it was a crude method for expelling poisons, meant to be used by inexperienced or inefficient Healers in the field – Kurt waited until he had slumped bonelessly onto the grass, eyes shut, before inching forward and pressing the second vial into his open, clammy hand.

There was a cold moment of fear that shot through him when the merman's raspy claws brushed his palm before he retreated to a safer distance a handful of feet away, clear of the mess. Thankfully, it was already disappearing – one of the many beneficial qualities of the potion; it evaporated quickly – by the time he sat back on his heels and waited.

The merman sniffed the vial twice, wary after his first encounter but surprisingly open-minded, given how horrific it had been. Kurt hadn't expected him to give it more than a passing thought, but he downed it swiftly and uncomplainingly, shuddering once as he did so.

Almost immediately, the vigor seemed to return to his face; color flushed his cheeks as his limbs trembled, his fingers clenching and unclenching as he twisted on the ground, caught between paradoxes as the potion took effects. He was weak from the purge but rapidly regaining his strength from the revitalizing potion.

He passed the last vial to him before the effects of the second potion began to fade, the merman's fingers trembling around it as he brought it to his lips and swallowed the mouthful without a thought.

Even knowing the effects of the numbing potion, Kurt still yelped in surprise when the merman's body began to slide further into the lake, his fingers tangling in the grass as he turned with a sort of wild panic in his eyes and clung to the grass, cheek pressed to the dirt. Without a moment's hesitation, Kurt lunged forward and caught him under the arms, tugging him back ashore until he flopped out of the water entirely, tail heavy and motionless behind him.

Clawing weakly at Kurt's arm, the merman hissed from between his teeth as he lay on his back, gazing helplessly up at Kurt as the numbness overtook him entirely, leaving everything but his head virtually immobile.

Suppressing his guilty conscience at putting the merman through even more inexplicable stress – no amount of miming could convey the necessity of the potion in order to safely remove the barbs – Kurt withdrew a pair of tweezers and set to work. Some things were too fine for wands, and Kurt was afraid that a spell might rip the barbs out with more than just bristle-covered ends. Setting to work with his Muggle tools, he extracted each of the barbed thorns from the merman's tail, ignoring the way it twitched minutely after each one.

Eighteen barbs later, the tail was barb-free, with angry red dots punctuating the places where the bristles had clung. Grateful that the worst was over, Kurt looked up at the merman and noticed his gaze skyward, patient and oddly thoughtful, unflinching in the face of his trials. He couldn't tell if the set of his jaw was merely from the potion or due to contemplation.

He got his answer when he shifted back onto his heels, the merman's gaze sliding to him as he tilted his chin up a little, almost challenging. He slowly tilted his gaze back down, looking at his tail with quietly thoughtful eyes.

The tension lay heavy in the air, and Kurt considered shuffling out of reach before the merman could fully regain his senses and repay him for his suffering, when at last the merman coughed, a scratchy, breathless sound, and tilted his head back onto the grass, eyes closed.

It was the closest thing to trust that Kurt had seen all night, and he relaxed unconsciously, the tension melting out of his own shoulders. He'd done something right, at last; he felt vindicated as he gathered the empty vials and tucked them back in his robes, wondering if he needed to assist the merman back to the water of if he would manage on his own. The numbing potion was already wearing off; the merman's tail flickered absently from side to side as he tested the limb with newfound painlessness.

"S-sorry," the merman rasped, entirely unexpected, and Kurt almost fell over despite being seated as the merman rubbed his cheek against the grass, evidently exhausted. Even with his sharp teeth and pointed ears, he looked gentle in that moment, brushing his face cat-like against the grass.

"Don't be," Kurt said, wondering how on Earth he was supposed to explain to Professor Cabot that he had stolen three of her prized potions in order to help a merman. "You – speak?"

"Less," the merman explained. "Less than – you. But – yes." Then, features twisting for a moment, the merman explained, "Hurt before. Less hurt, now." Elaborating, he grated out, "Sharp pain first. Then dark. I was – drowning. Crawled to – to land. Found you." Looking up at Kurt, he amended, "You – found me?"

Nodding, Kurt waited for him to continue. When the merman didn't speak, he asked, "I found you. Yes." When the merman made a soft, vaguely musical sound, somewhere between a groan and a hum, he admitted, "I've never actually met a mermaid before."

Grinning with those wickedly sharp teeth, the merman said, "Never met human. Strange." Then, tilting his head to look at him, he added accusingly, "Painful."

"Necessary," Kurt clarified. Seeing the merman's blank look, he added, "Good pain."

"No pain is good pain," the merman countered.

Kurt couldn't help but nod his agreement. His gaze flicked instinctively to the merman's tail when he flicked it thoughtfully. "Is it – sensitive?" he asked, genuinely curious.

"Strong," the merman corrected. "Like – " And then, heedless of how intimate the gesture was, the merman leaned forward and lightly raked a hand from the top of Kurt's thigh to his knee. "This," he finished.

Shivering in spite of himself – it was cold, but even Kurt knew that he couldn't blame the cold with the warming weather – he tightened his cloak around his shoulders, looking at the merman's unclothed body and asking, "How do you stay warm?"

The merman looked up at him with slitted eyes, wary. "Humans are sensitive," he said at last. "Not us." Tilting his head to stargaze a moment, he added, "Late. You – sleep?"

"I do," Kurt agreed. "Or, at least, I should." Perfectly aware of how late it was but loathe to leave his new companion – how often did anyone speak with mermaids? – Kurt asked the only thing he could, "Can I see you again?"

The merman frowned at him, neither cruel nor entirely understanding. "Next moon? Yes."

Willing to take whatever he could get – any opportunity to converse with a mermaid was fine by Kurt – he nodded, watching as the merman slowly shifted towards the water again, his movements smooth once more.

"Thank you –?"

"Kurt," Kurt supplied inanely.

The merman blinked, already half-submerged. "Kurt," he repeated, struggling to wrap his tongue around the syllable. Then, more authoritatively, he looked into Kurt's eyes and said simply, "Kurt."

"What's your name?" Kurt asked, already watching him vanish, mystified.

The merman flashed him a smile and for a moment Kurt was convinced that he wouldn't say.

"Blaine," he said at last, ducking under the water and vanishing, ripples trailing after him until he was gone completely.

Blaine.

That night, Kurt dreamed of Blaine – of a downy watery bed and a blue-tailed merman curled up on top of it, his scales shimmering as he slept, bubbles emitting from his mouth.

Hogwarts was full of mysteries, Kurt knew, many of which would never be fully understood; but most of all, he was entranced by the mystery that was Blaine the merman.