GreenWithAwesome here, writing my first Mortal Instruments story! ... With PJO! ;D Hope you enjoy it!

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The monster in the middle of New York should have been easy to kill.

But no. Things never went the way Percy wanted to, did they?

In actual fact, the monster was super easy to kill. Pretty low class, dumber than a brick wall. Perhaps one of Tartarus' expendables. It meandered around the alleyways of the Broadway Theatre district, its soulless face shooting shivers down Percy's spine. Thick buboes littered his skin in ugly tumours, so green he could have started the evening traffic, if mortals could see it.

A few strokes of Riptide to its throat would have caused it to explode into shards of dust and trail back to whatever crevice it had crawled from. And though Percy was hardwired with the awesome, hypersensitive instincts of a demigod, and trained to levels that Chuck Norris would be jealous of, he sure wasn't prepared for this.

As the monster plunged deeper into the shadows of the alleyway, dodging all the neon lights of New York's vibrant borough, Percy sidled the wall of brick, the chill of winter's breeze curling around him. It bisected the back streets of two tattoo parlours – the cement ashened with graffiti – and would eventually lead to the front entrances. He peered around the corner, knowing he preferably wanted to send it packing before some passer-by mortal happened to catch a glimpse of whatever the Mist provided – maybe a really fat rat, or a homeless old guy that made someone nauseous. He noted at that odd moment that though it stank of the overwhelming scent of Eau de Ugly Greek Monster, he didn't recognise what it was.

Maybe it was more powerful than he anticipated.

It continued to lumber aimlessly down the alleyway, nearing a turn in the path to the left. Percy could taste the metallic air weeping from the unclean alley: trash cans overturned, rubbish marinating the path, the abandoned cardboard boxes of the vagrants trying desperately to fly free. The monster ignored all of this – even stepping on a banana peel with ignorance.

Percy waited. It didn't fall. He couldn't help but feel disappointed that this wasn't one of those cartoon moments.

Now it was sufficiently hidden in the darkness. Percy whipped out Riptide from his pocket, uncapping the pen, and drawing himself forwards to reveal his figure in the alleyway. If he continued to creep, the monster wouldn't know what hit him. He trod carefully over the rubbish, keeping his breath steady, Riptide raised above his head. In a few moments… just a few more steps… Percy could strike-

A sweeping effigy caught his vision, just before he unleashed his weapon – a streak of white gold, whiplashing from the sky to the monster, flashes of bright silver flying out.

The person fell to the monster – but a nonchalant swipe of its arm punched them backwards. Right into Percy.

"No-!" Percy didn't have time to finish his sharp inhale of breath as a guy, clad in black leather, cascaded head-first in Percy, throwing them both into a spiral down to the ground. The grit and dirt of New York alleyways grazed onto his face, his clothes, and ripped his grip from Riptide away. It skittered further back, just as Percy regained his bearings. He opened his eyes, which had clenched shut from the fall.

He was staring face-first into the yellow eyes of a neo-punk goth with a weird fancy for exotic tattoos.

Immediately, the boy threw himself off, "What the hell-?"

He didn't have time to finish either, as the monster, now angered, turned to face them – it bore its teeth like the serrated edge of a knife, the giant spots on its skin pulsing in eerie glows.

Percy scampered backwards to grab Riptide, and the boy picked up the weapons he dropped: two giant kitchen knives. He surged forward to stab the creature in the chest, but – with blinding speed – it whacked his first blade away, and the second striking his face. He staggered backwards and fell against the wall, stumbling over a crate filled with rotten mango skins and buckling to the floor.

This was the time to shine. Percy gripped at Riptide and sprinted forwards, to save the day and be awesome, but the monster retaliated by grabbing a steel barrel and flinging it at him.

In slow motion, he watched the barrel shoot through the sky as if a star, catching the sparkles of stray light and glittering with rust.

It walloped Percy in the face. He skidded to a halt – only to catch the banana peel and slip with an unnerving crack to the floor. He let out a cry, a hyena's mating call, as pain cradled his body. The monster let out a mighty roar and trudged down southwards and to the left, disappearing from sight.

Percy lay in silence for moments, contemplating his life, as a barrel sat on top of him like a iron elephant, and a banana peel glued to his shoes as if he'd tried to make banana skates. Percy didn't really believe in karma, but if he did, it was laughing at him right now.

The blond boy grunted with displeasure, standing up, stripping himself of dust and random strings of loose, brown mango.

"That was a disaster," he muttered, retrieving his giant kitchen knives and slipping them into the sheaths of his belt. Percy could barely detect him as he blended so well with the shadows – everything but his skin and hair, black. Intricate weavings of ancient tattoos laced the visible patches of skin, which were more frequent since his scuffle with the ground.

"You're telling me," said Percy, rolling the barrel off. The insignia of Camp Half-Blood had worn away.

"I am telling you," said the blond, "You messed it up."

"I messed it up?" Percy repeated, coming to a stand. The blond was taller, and older, and with an unmistakeable aloof expression. It reminded him of Nico, although whilst Nico still had some boyish charm, this guy looked like he was trying too hard to be mature, "Dude, I totally had it. I could have killed him if you didn't come dropping from the sky like a fallen duck."

He seemed to cringe at the expression, yet still managed a sneer, "I think you'll find I have the grace of an angel, thank you."

"That's a funny way to say 'duck', but whatever floats your boat, man."

The blond boy drew in a breath, "You shouldn't even be able to see me, or that thing, mundane," he spoke, his words a sharp as Olympus spires, "I had everything under control."

Percy tried hard not to let his annoyance show, "Well, I suppose you can see this-" he held up Riptide, and the blond nodded, "Which you shouldn't be able to see either."

He flashed his eyes, golden plates of armour – guarded, just as Percy felt, "Sorry to disappoint you. I'll have a word with my optician about how to worsen my eyesight," he snorted. Percy felt the volcano inside him bubble, "But it's clear we have common goal. I will say that."

He'd noticed. Though the blond guy seemed to be from another planet, another realm even, this happened to be the one task that aligned their paths, "He's probably gone round to the front."

"Doubt it, that demon is too slow."

Demon? Percy didn't question. People could call monsters whatever they wanted.

He resisted a smirk, "So slow that he slapped you in the face like a drunkard. Sure."

The boy said, "Who are you anyway? A shadow hunter?"

Percy scoffed, "I ain't Peter Pan, dude." He held off for a moment, hoping to change the subject – but it was curious. How did this guy see his weapon? Celestial Bronze was invisible to mortals. Was he a demigod too? He didn't look like any demigod Percy knew, or dress like one – he could have been a wayward model for Hot Topic for all he knew. And there wasn't exactly a feeling of obligation to reveal his true colours to a guy he'd just slammed into.

"… We kill demons," the blond said, with hesitation. Clearly, he didn't like sharing details of himself to strangers either.

"… So do we," said Percy, "Monsters, we call them."

"Bit of a namby-pamby name, isn't it? I mean, oh no, there's a monster under my bed sounds far less menacing than oh no, there's a demon under my bed," he shrugged, taking a step down the alleyway, "Look, kid, it's clear your sword is too much for you to handle, so let me go after the demon. I don't need you getting in my way trying to play soldier." He moved to out of the range of lethal fruit skins to take his leave, but Percy found himself right behind him.

"Says the guy with over fifty weapons stashed in his pants," the blond guy moved off and Percy kept pace. He scowled.

"And it doesn't put you off," he said, "Great."

The boys turned the corner. They were met with a lattice of new obstacles – more bins, more spilt rubbish. The demon-monster-whatever had obviously taken the time that they were exchanging witticisms to slink around the next corner. Percy didn't know how many corners they could spare before it unleashed itself into the world.

No matter what he said, Percy thought, there was no way the blond guy was letting up. He was either going to have to team-up with him, which wasn't preferable, or kill him, which – as the sarcastic barracks that he was – also wasn't preferable. They sprinted through the next alley, dodging the skins, dancing over rotting wooden planks and dipping under some random washing lines that had somehow made their homes in the hollows of New York's worst.

"At least tell me your name, if we're working together," said the blond, skiving a barrel, "So I don't have to keep calling you 'kid'."

Percy inhaled a breath as he ran, "Percy."

"… Kid is shorter," he muttered, wisps of air following his mouth, "Jace."

"Lucky," he replied, "Jace is shorter than Gothic Blond Guy."

The words seemed to make him smile, but their paces didn't quicken. Jace launched one foot in front of the other, his strides long and consuming. Percy reckoned he was a tall guy, for his age, but Jace towered above him in spears of black and gold steel. He made an impression at least, his presence jarring and unmissable.

"We really only need to stab him a few times," Jace's dark voice pierced the air in cold bursts, "Something as simple as that. I'll go for the front, you stab from the back." They swerved the corner, met with another corner closer than before. Percy's mind bungled when he tried to think about where he was.

"You know, I can use my sword," he said, leaking irritation into his tone, "I've been training for four years."

"That's cute," said Jace – they approached the corner, snootiness in return for irritation, "I've been training my whole-"

He slipped – something underneath his footing giving way – and slammed into the concrete with a drastic crack. His blond hair wildly gesticulated around, until he settled into the ground. Percy skidded to a halt, and backtracked.

"You alright?" He resisted another smirk. So much for his lifelong training regimes.

Jace looked up, dazed. Cuts split his skin and sliced his lips. Blood dribbled from his nose, an uncomfortable position on his face. He cursed a string of profanities, before sitting up.

"I'm fine," without another word, he slipped a hand into his boots and pulled out a thin, prism-shaped object, filigreed webbed into its design. He gave it a jolt and the glass-like part of the tip glowed in furious electric blue.

"… Nice crayon," Percy said. Jace didn't even regard him, or grace him with an explanation as he rolled up a sleeve and started to draw tattoos on himself, the tip sparking as it contacted his skin. He wiped his bloodied face with a sleeve.

"Go after the demon," he muttered, jerking his head in the direction of the path, "I'll catch up." He spat out some blood as he said so, and Percy nodded.

Not like he needed his help with it anyway.

Percy shot off, Riptide swinging in his grip. He skirted the corner and another, before he finally caught the monster – mulling around the next and final corner. Bright neons slithered around its skin, vibrating into different hues as it moulded with the darkness of the alleyway. Percy could see the monster begin to step into the light, its lifeless eyes gleaming.

He ran forward, yelling – the monster caught his voice and stopped, turned in sluggish movements. Percy swung; the monster cried out, scrambling backwards from the momentum. Unfortunately, he'd done no damage to his actual skin. He'd grazed its pulsing zits, green ooze leaking from the point he'd struck.

A wave of bile brushed against the walls of his stomach. He pushed it down. Why were monsters so gross?

He jumped to the side to avoid an incoming punch, its fists as thick as stone plating. He crushed himself against the wall to narrowly avoid touching the giant spots, and stabbed out Riptide into its arm. The thing cried out again, swining; Percy ducked without Riptide in hand to avoid another ear-splitting moment, the thing relentlessly attempting to pull out Riptide, wedged right into its skin.

Percy backed up, weaponless. Right now, he really wished he had fifty weapons stored in his pants.

Finally, the monster, after much twirling in agony, pulled out the sword. It sliced open a bubo –and the contents spluttered alive, covering Percy in a thick paste.

He had to think of anything else to keep his lunch down.

"Missed me?" Jace's voice cut through the silence, jumping into view from behind. His kitchen knives were in his hand, aglow from the dim reflections of light. His nose was no longer crooked, and his face only left smears of dried blood.

"That's one heck of a magic crayon," said Percy.

Jace only glanced sideways towards him, before his focus turned to the monster, "Only a magical tissue could clean you up."

"And your magic crayon can't draw me clean?"

"It's a stele," Jace corrected, advancing forwards – he paused, slipping a hand down his boots and drawing out a knife, a decently sized knife, and handing it to Percy, "Might not be your style, but at least you're armed."

He'd had some practice with knifes, and had trained with Annabeth, who frequently used them. It felt lighter in his head, the steel smooth against his calloused skin.

"Ithuriel," Jace drew himself forwards – the monster used Riptide and swung it aimlessly at them. He blocked, the collision gilded, sparks crying out like fireworks. Jace brought Riptide upwards with one blade and stabbed with his other – it hit a rib (or whatever monsters had), near-missing another tumour filled with ugly pus.

Percy rounded them as they fought. Unguarded behind, Percy slashed with his knife, the blade carving stripes of wound across its back. Buboes exploded, coating him in more slick and stench-ridden slime, but Percy continued, latticing its back.

The monster fell to its knees. Jace stabbed it again, it crying out, pus fountaining around. The floor flooded in nasty slime, making standing more difficult. The two boys sliced and slashed, wounding the monster to its dying breath. Percy drove the knife in the back, and Jace his blades in the front, and with a final, raspy gurgle, the monster dissipated into ashes, dissolving into thin air.

Percy regained his breath – unaware of how much air he drank in until now. He wiped away the pus that was drying on his cheeks like a facemask of death. Jace was much the same, fresh slime glazing him like a mouldy Krispy Kreme doughnut. His breath heavily inhaled air.

"Green is not your colour," Percy said, with a sly grin. Jace just shook his head, also with a grin.

"What a shame, I always liked clothing by demon designers," the boys shrugged off as much slime as they could, joining the sludge pile painting the ground. Percy could feel it stick to his hair like dry conditioner, though a lot smellier than any dry conditioner he'd want to use.

"Well, then," Jace began again, "I suppose that's it." He removed himself from the slime pile, his boots making a long schlock sound as they unattached themselves from the green sea.

"I guess it is," said Percy, his trainers sticky and green. He really hoped the laundry services could take it off. He stood by Jace and held out his hands, "Nice to meet you."

Jace wavered, his hand jerking slightly. But, he did hold out his hand to shake. It was a firm grip, clammy from use, but solid. Percy wouldn't want to have been on the receiving end of one of his punches.

Jace's voice was barely audible, "Seriously though, who are you?"

He thought about it for a second.

"Let's just say I'm only half human."

To that, the blond laughed.

"Same here."

They released grip, and Percy watched him give an unenthusiastic salute and spin on his heel, eventually melting into the shadows that he so well embraced with. He could see gold tints flash with danger as he turned the corner, away on another adventure.

Percy just smirked. This job could have been so much easier if the Jace hadn't showed up, trying to be an angel elegantly swooping from above and committing acts of monster-genocide for the good of the people.

He scoffed, turning towards the exit of the alleyway and returning to his quasi-normal life as the demigod son of Poseidon.

"Pfft. Angel. What a joke."

Fin.

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Hahah, this idea came to me randomly and I wrote it within the space of about three/four hours. I feel as if the narration from Percy's perspective is a bit too detailed (for a male narrator), darn Clare influencing me, but I'm still pleased how it turned out and I hope you enjoyed it nonetheless! And I hope I managed to grasp Jace and Percy's personalities, too!

Please bare in mind, whilst I am aware of certain details, I haven't finished reading City of Glass, so please refrain from posting spoilers, thanks. As for PJO, go ahead and post anything you like since I'm all caught up there, lol.

Thanks for reading! Leave a favourite/ follow/ review if you'd like to!

~ GD