Aquatically outmatched

After quite some time poring over history books in Hyrule Castle, a rito bard, Kass, made an interesting discovery: More than one ancient hero had used strange, magic songs, which had effects on the environment. Even knowing said songs existed, it still took a while for the rito to find more detail about any in particular. The first one he discovered, the "Serenade of Water", allegedly had ties to an extremely old temple somewhere around Lake Hylia... With a burning curiosity, Kass practically had no choice but to set out there to see whether the song truly had power!

It took the better part of a day of searching, but the temple's entrance was finally found, a small cave leading to it. Even with it getting late, Kass' excitement outweighed him being a bit tired, and he started making his way inside after some hesitation. He wasn't much of a fighter, and while he could probably just fly away from any monsters he found, this was his first time going into a place like this. But, with how old and out of the way this place was, there was a decent chance he wouldn't have any sort of encounter.
Before long, the path started to dip down, water covering it... And eventually, the only way forward was underwater. Kass sighed, not being the biggest fan of swimming, and backtracked some to find a dry place to put his things until he returned. Leaving everything behind - even his clothes, as he hadn't brought swimwear - he returned nude to where he'd need to dive, and prepared with some deep breaths. He was at least good at holding his breath, managing about 14 minutes on average, so the water itself certainly wouldn't be a worry. Eventually, with a last deep gasp, Kass shut his beak and puffed his cheeks before diving in, starting to swim along the passage.
After about 30 seconds of swimming, Kass arrived at quite a large chamber, seemingly having multiple floors below him. Instead of swimming down there, he got himself above an open section and let himself sink to save his energy. As he went deeper, he thought about just how far he was going to need to swim to breathe again... He found himself starting to get aroused at that, and he couldn't help but give his cock a few strokes as he sank.
Once he was just above the bottom, he began swimming again, entering into a different passage. It led to another tall room that he was at the bottom of, though one that was quite a bit more narrow than the previous one. Swimming up that, Kass' time underwater ticked up to 2 minutes by the time he'd reached the top. There were a couple doors here on opposite sides, both having long ago fallen apart due to age, though with their doorways thankfully intact.
Picking one at random, Kass swam through. The furniture in this room was so decayed he couldn't even tell what the room's purpose was, but he searched around for anything interesting anyway. With nothing found, he left to check the opposite room, which was similar apart from him finding a handful of rupees. It was always strange to him how Hyrule had used precisely the same currency for millennia...
Holding onto the rupees for now, he returned to the middle and let himself start to sink again. The rito's need to breathe was making itself obvious to him by now, but he didn't mind just yet. In fact, part of him was quite enjoying it, his cock now fully erect, and he took another break to masturbate while he sank. All this time holding his breath and diving in this unfamiliar place was doing wonders for his arousal, but he didn't manage to finish before landing on the bottom once again.
After swimming out to the main room again, Kass had been holding his breath for about 4 minutes. He blew a few bubbles to help relax his lungs a little, and just kept on exploring, wondering if he might be able to see the whole temple on a single breath. Room after room, minute after minute, he mentally mapped everything out... Eventually, his breath hold got into the double digits, the rito starting to struggle. He believed there to only be a few rooms left now, but something other than his lungs was really beginning to demand his attention.
His neglected cock had been throbbing between his legs for several minutes by now, and Kass couldn't ignore it any longer. Even as he continued to swim, his need to breathe forcing out the occasional "Mmh" or "Rk", he reached down to masturbate again. Since he'd left the rupees in the main room a while ago, he could still swim pretty much fine while he took care of himself. Slowly, his grunts of strain started to be accompanied by muffled moans of pleasure...
Another minute, and Kass stopped, covering his beak with his free hand as his arousal started to surge up. Despite trying his best to keep his air in, he let out another muffled moan, sending both some bubbles and cum into the water with a heavy, well-earned orgasm. It helped distract him from his need to breathe, but that didn't last long, continuing to cover his beak as his face just began to gain a purple tint.
As badly as he needed to breathe, Kass kept going, knowing he had plenty of time to get back outside. Soon, he came to yet another room, this one actually having an intact pot in it, the first he'd seen in the temple. With a shaky hand, he pulled off the pot's lid, and a head-sized air bubble floated free! After a moment of hesitation, thinking about how it might feel to inhale such old air, Kass decided to go for it, catching the bubble and bringing it to his beak to inhale. The air didn't taste the best, but had plenty of oxygen to give, removing the purple tint from the rito's face and refreshing his breath by a substantial amount. Estimating that it had bought him another 8 or so minutes, Kass smiled and resumed his exploration, now only feeling just a nudge in his chest of his lungs asking for more air.
As he went on his way to another room, he heard what sounded like wood breaking... And as he swam into the room, he discovered why: There was a chameleon-like creature, about as big as him, rummaging through a broken crate, one of its eyes scanning around the room while one stayed focused on the crate's remnants. This was a lizalfos, the worst monster he could have found in here! While they were thankfully at least unarmored, Kass immediately ducked out of view again, knowing he almost certainly wouldn't stand a chance if they saw him. After a few seconds, he peeked around the corner, seeing the lizalfos pick something from the crate... And its free eye happen to look directly at him.
Both Kass and the lizalfos froze, staring at each other. The monster turned their head to get a better look at the rito, and with a smile, bolted toward him! Kass tried to swim away, but let out a bubbly yelp as he's yanked backward into the room the lizalfos had been searching. "GABLAH!" He was thrown across the room, nearly slamming into the opposite wall, and he fearfully looked at the monster... Before he balled up his fists. He'd certainly never fought underwater before, but he didn't really have a choice here.
As the lizalfos figured out Kass intended to try to fight, they cackled at him before they rushed him again, using their momentum to give him a powerful punch to the gut before he can react. "BLOUGH!" Bubbles burst from Kass' beak as air got forced out of him, and he quickly grabbed it to shut it again, before swimming forward to-
Take another punch to the gut, pushing out more bubbles. "HBLURGH!" After holding his beak again, Kass thought about how odd this was. If this lizalfos wanted him dead, he'd already be gone by now, so what was it doing? As they charged forward again, he covered his stomach, blocking their next attack. This one made it clear to him; they didn't want to directly kill him, they wanted to knock his air out so he'd drown!
The lizalfos got a bit of distance again, then started to rapidly swim to him again, prompting the rito to cover his belly again... Before he was punched in the face instead, burbling once again, but mainly from pain this time. "ABLABLBL!" Just staying on the defensive wasn't going to help; as unlikely as it was that he'd win, Kass had to try!
This time, when the lizalfos swam back, Kass chased after them, taking a swing at them and completely missing. They grinned at him as he went for another, and another, but he just couldn't hit them. Swinging wildly wouldn't do it, he needed to focus... Trying his best to predict what the lizalfos would do, Kass focused on them and nothing else. When they rush him again, he correctly guesses they're going to go for his belly again, barely managing to dodge out of the way and finally deliver his own punch to their face while they're open.
There's a hiss of pain as the lizalfos is struck, and they push Kass away. The rito smiles some, glad to have hurt them at least a little, but now his need to breathe is starting to occur to him again... "Ghk...HMRGH!" In his moment of distraction, the lizalfos goes for another attack to his gut, and while it lands, he just barely manages to keep his air in, starting to get used to the force by now. Then, another attempted strike to his face, which he manages to dodge and counter like before, hitting the other side of the lizalfos' face and making them recoil again.
With Kass starting to get the hang of underwater fighting, the lizalfos changes up their strategy. Instead of simply charging like before, they lash out their long tongue, yanking him toward them! "PLABLABL!" Caught off guard, Kass takes another powerful hit to the stomach, knocking out another cloud of bubbles. He was getting low on both air and breath at this point, and while he tried to push away from the monster, they continued to hold him, pressing his back to their chest. They move their head into his field of view, smiling at him as they feel up his heaving chest. "Mm...Mmm?" It seemed their choice to try to drown the rito wasn't just out of convenience; the lizalfos was an aquaphile.
There's another hiss as Kass drags his talons on the lizalfos, and it pushes him away again. He hadn't drawn blood with that, as much as he'd wanted to, but it clearly did its job. As he turns, and before he can get a chance to prepare again, he's pulled to the lizalfos once more, and they go for an especially hard hit this time, stomping Kass' belly. "HUBLRGLBL!" The momentum from both movements finally completely knocks the wind out of him, an especially big cloud of bubbles being let loose. Kass instinctively sucks in, but gulps the water before it can reach his now empty lungs. The lizalfos gives him another quick punch to the gut. "Hmg!" With barely any air being let out, they grin, knowing it's almost time.
The airless rito is shoved across the room again, and the lizalfos happily, casually swims to the doorway, simply watching him struggle now. Kass fearfully looks at them while covering his beak, letting out pathetic, tiny whines as his face goes purple again. The lizalfos starts to masturbate, stroking both their cocks and making it clear they don't consider him a threat. It reminds Kass of his own arousal, which had returned during the fight, his own cock now throbbing once again. Unwilling to take care of that right now, and knowing he won't get back to the surface in time any more, he starts frantically searching the room, looking for air while the lizalfos enjoys watching his struggles.
Only half a minute later, Kass curls up in a last, desperate struggle to hold on, barely even having enough air to whimper as he reaches the edge of both cumming and gasping... "Ghk, mmng... G-GHUUUAA-GARGL!" Before, finally, he does both. Arching his back, he opens his beak wide to suck in a deep breath of water, and his cock starts to spasm and spurt cum for the second time on this dive. As he grabs his neck, choking and thrashing, the lizalfos has an orgasm of their own, tightly shutting their eyes and letting out a much more pleased hiss as they too begin filling the water with cum.
"HURK! GLK, HUU-GURK!" As Kass' orgasm dies down, he frantically swims for the doorway, and with the lizalfos having their eyes closed, they don't yet notice. Then, he accidentally grazes them with one of his arms, alerting them to his attempted escape. They quickly turn and try to grab him, but they miss, and then simply use their tongue again to pull the rito back into the room. Kass, of course, doesn't give up, continuing to try to get past the lizalfos, but his panicked swimming is always easy for them to intercept, pushing him back into the room each time.
This goes on for almost 30 seconds, before it starts getting even easier for the lizalfos to prevent Kass' escape as his struggles die down, his body losing its energy. Soon, Kass can't even swim any more, and the lizalfos holds him to their chest the same way as before. Bringing their head close to his, they happily listen to the dying rito's aquatic breaths, with him helplessly struggling in their grip, throwing clumsy punches that look more like weak flailing. An occasional hiccup makes his body jolt, his toes splaying, and the lizalfos puts a hand on his chest to enjoy as much of his drowning as possible.
"Gurgurgl... Hic-ulp... Mmnhuu..." Kass lasts for an amount of time that's surprising to the lizalfos, his breathing gradually slowing, getting more shallow as his face goes entirely blue, an occasional watery plea being audible. "...P-plleasse... huu... l-llet gho..." After a solid minute of this waterlogged breathing, the rito's eyelids begin to droop, and as his beak opens wider to take one last deep breath... He jolts back to awareness, the very last of his adrenaline rushing through him! The sight of this second wind stuns the lizalfos, and before they can react, they're punched in one of their eyes!
Screeching, the lizalfos lets go of Kass to hold their eye in pain, giving him a chance to start swimming away again. Before he can get far, the lizalfos glares at him, and keeping their hurt eye closed, grabs him with their tongue once more to pull themselves toward him, then yanks on his ankles to slam him to the floor! "HIC-GHUUUAAA!" Kass hiccups and involuntarily takes a huge gasp, freezing up... And staying still, his body's energy entirely used up at last. 
The drowned rito lays on the floor of the ruins, eyes wide, pupils growing as his vision fades. He feels his dick spasm and shoot out cum one last time, a light shudder running through his now lax body. “glk...” This last orgasm fades, and Kass’ mind finally slips away from him, leaving him to stare blankly at nothing. To sleep...
Rubbing at their eye, the lizalfos finally recovers from the hit they took, and looks at Kass' body with a smile. As much of a fight he'd put up, they'd definitely enjoyed this quite a lot! He swims over, checking the Rito’s neck for a pulse. None. He looks at Kass’ still wide open but lifeless eyes, the last remnant of his desperation. It was his favorite expression, a sign of a job well done. And his dick was still hard too, though he knew it wouldn’t spurt cum ever again...
Not particularly interested in continuing to explore, as they'd come here looking for fish to eat and hadn't found any, they swim from the room and head toward to exit, leaving the dead rito on the floor to settle into his final resting place.