Rin’s muscles ached in that familiar, satisfying way that only came after a punishing swim practice. He slung the damp white towel over his broad, pale shoulders, the scent of chlorine clinging to him like a second skin. The pool deck was mostly empty now, the echoes of splashes and coach’s whistles replaced by the hum of filtration systems. His mind, however, was anything but quiet. Finley. He hadn’t heard from his sister in three days. It wasn’t like her. Not at all. A low thrum of anxiety vibrated beneath his ribs, a constant companion these days. He needed to get back to his dorm, find a quiet corner, and call her. Properly.

He was halfway to the locker room doors, his large frame moving with a quiet, almost apologetic gait, when a sharp, grating sound cut through the hum—skin scraping violently against the rough tile edge of the pool. His head snapped toward the noise just in time to see a figure wincing as they pulled a badly scraped elbow out of the water. A dark, swirling plume of crimson immediately began to cloud the blue.

Oh, strewth. Rin recognized the other person from around campus- though he considered them a stranger or an acquaintance at best. He doesn’t even remember their name, though they have a class or two together.

Rin’s first instinct was concern, a genuine, human worry. “Hey! You alright?” he called out, his voice echoing a little too loudly in the cavernous space. He glanced around, searching for a lifeguard, another swimmer, anyone. The deck was deserted. His eyes darted back to the injured student, who was now clutching their arm, the blood flowing more freely than a simple scrape should allow. The metallic tang hit his senses then, not as an explosion, but as a slow, insidious seep into the chlorinated air. It was... sweet. Unusually so.

“Hang on, mate. Let’s get you out of there,” he said, his tone practical. He waded into the shallow end, the water cool against his legs. He offered a hand, his movements careful and deliberate, helping to steady them as they climbed out onto the deck. “C’mon, first aid kit’s on the wall. Reckon you’ll need more than a band-aid for that one.”

He led the way, his mind focused on the task. Find the kit. Clean the wound. Stop the bleeding. Simple. He retrieved the white plastic box and knelt, popping it open. The scent intensified as he got closer, a rich, copper note that curled in the back of his throat, far more potent than any blood he'd ever smelt before. He focused on the contents of the kit, laying out gauze and antiseptic wipes with hands that were, for the moment, steady.

"Right, let's have a proper look," he murmured, his Aussie drawl softer now, more concentrated. He gently took their arm, his touch surprisingly deft for someone with such large, blunt-tipped fingers. The scrape was nasty, a raw, weeping furrow across the skin. "Bloody hell, how'd you manage that? The edge of the lane divider?"

As he spoke, he tore open an antiseptic wipe. But as he went to clean the wound, his thumb, seemingly of its own accord, brushed against the skin just below the cut. It smeared a single, perfect droplet of blood in a thin, crimson line down their forearm.

A jolt, electric and visceral, shot up Rin's arm. His breath hitched, the air catching in his suddenly tight throat. The scent wasn't just strong; it was compatible. A biological match that resonated deep within his shark-demi DNA, telling him this blood was perfect. This person was his.

His hands began to tremble. He tried to press the wipe to the wound, but his movements became jerky, uncoordinated. The low, mechanical hum he’d been suppressing vibrated to life in his chest, a deep thrumming that was felt more than heard. He risked a glance up at their face, his red eyes wide, pupils beginning to narrow from round pools to hungry slits. "It's, uh... it's deeper than it looks," he managed, his voice dropping an octave, losing its casual friendliness.

He tried to focus on dabbing at the scrape, but his attention was fractured. The scent was intoxicating, crawling into his brain and smothering his better judgment. Each time the clean gauze came away stained red, his breathing picked up, becoming audible—short, sharp inhales through his nose. The gill slits on his neck flared subtly, trying to drink in more of the irresistible fragrance. The part of him that was all instinct, all predator, was surfacing, and the skittish boy who just wanted to help was rapidly losing the battle.

The antiseptic wipe was a lost cause, a pink-stained mess clutched in his shaking hand. Rin’s world had narrowed to the raw, glistening scrape on their elbow and the coppery-sweet scent that was now a thick fog in his head. The rational part of his mind was screaming, a distant alarm bell—Stop. Stop now. You’re scaring them. You’re a monster.

But the hum in his chest was louder. It was a purr of pure, primal satisfaction that vibrated through his bones. His thumb, which had been clumsily trying to apply pressure, stilled. His gaze was locked on the thin trail of blood his touch had smeared.

"I... I'm sorry," he breathed, the words a ragged whisper that was more for himself than them. "I can't... It's too..."

His sentence died as he leaned forward, his movements slow, hypnotic, almost trance-like. The struggle was evident in the tension of his neck, the white-knuckled grip of his free hand on his own thigh. But the predator had won.

He closed the final inch of distance, and the tip of his tongue, surprisingly soft, darted out to lick a slow, deliberate stripe along their forearm, cleaning the smeared blood.

The taste was an electric shock to his system—a thousand times more potent than the scent. It was rich, metallic, and alive, a flavor that resonated with something ancient and hungry deep within him. A low, involuntary groan rumbled in his chest, a sound of pure, unadulterated need.

And then, he froze.

His entire body went rigid. The reality of what he had just done—the intimate, feral violation—crashed down on him like a physical blow. His head snapped up, his widened, slit-pupiled eyes flying to meet theirs, horror dawning on his pale features. The hum in his chest cut off abruptly.

He recoiled as if burned, scrambling backward on the wet tiles, putting a few feet of desperate distance between them. His hands came up, not in a threatening way, but in a gesture of pure panic, as if he could physically push the moment away.

"Shit. Shit," he choked out, his voice cracking, the deep predatory rumble gone, replaced by a terrified, skittish stammer. "I'm—I didn't—" He wiped the back of his hand across his mouth, staring at the faint red smear left there with utter disgust. "I'm so sorry. I lost... I lost control. I... I have to go."

He looked utterly shattered, the feral confidence evaporated to reveal the deeply anxious boy underneath, now terrified of the monster he’d just become. He began to push himself to his feet, his movements clumsy with shame, ready to flee.