Hi everyone! I have been waiting forever to post my PJO/HP crossover and I can't wait to share it with you! Here are the basic specs:

Stygian is a crossover that takes place during Harry Potter Next-Gen (but without the effects of The Cursed Child) and the children will show up, but the only one that is featured prominently is Teddy Lupin. Nico is twenty-two years old, Teddy is nineteen, and Neville is in his late thirties. This will update bi-monthly whenever I have time or inspiration as Corinthians is my main priority and this fic is a bit of fun.

Enjoy!

Nico di Angelo stood as he often stood his entire life: on the edge of a precipice. The dusty leather of his shoes kicked rocks off the sheer cliff face where the sea swallowed it eagerly. Waves writhed against the boulders below. He didn't dare peer over the edge.

It was a beautiful day in southern Italy, too beautiful by Nico's standards, but months of living abroad have led him to adjust the standards by which he conducted his life. Time felt different in this part of the world, two bright ribbons stretched into oblivion on either side of him. If he turned his head just right, he could see the past, and a tilt to the other side meant a glimpse into the future. Nico knew if he wanted to, he could reach out and grasp it, but his hands stayed where they were in his pockets.

He had no time for wishful thinking.

But that, too, was wrong. Nico had all of the time in the world now that he'd uprooted himself from his cramped studio apartment in Brooklyn and the darkened cabin he'd left behind years ago at camp. In renouncing a future of quests and adventures, he'd inexplicably unmoored himself from the path that most demigods were set on until an untimely death caught up to them.

Nico di Angelo didn't think he'd enjoy being purposeless, but that was another thing he'd proved himself incorrect on. Being able to float through life, getting by on what he could covertly steal from food carts or buy in exchange for a favour gave him a new outlook on life.

Namely, that life wasn't nearly as important as everyone thought it was.

His friends had long since learned that getting in touch with Nico was a fool's errand if there ever was one. The lucky few that recieved an Iris message from him could expect them once every few weeks. Nico thumbed the golden drachma in his pocket and, with a resigned sigh, threw it into the rainbow produced by the sea.

"Oh Iris, goddess of rainbows, please accept my offering. Percy Jackson, New Rome," Nico said. He sat down at the edge of the cliff, his legs dangling off the side.

A hazy image of Percy shimmered into view. He was washing dishes in a small kitchen; the TV on in the living room behind him blaring a colourful children's cartoon. Percy jumped at the sight of Nico, nearly shattering a wine glass.

"Nico!" Percy broke into a grin. "How's it going?"

Nico shrugged. "The same. It's gotten ungodly hot here. You'd love it."

"Well it's been pretty hot in New Rome, too." Percy resumed washing the dishes. "Where are you living these days?"

Nico bit his lip. "You know I can't answer that."

"Fine," Percy sighed. "We're planning a visit back to New York this weekend to see my mom. Annabeth thinks she finally cracked how to get Nate to settle down on planes: apple juice."

"What, no cross-country road trip?" Nico cracked a smile.

Percy laughed. "God, I hope not. As much as I hate planes, I'd hate taking a two-year-old in a car for that long. I get enough of him at home."

"He's your kid, Percy. You had him on purpose," Nico said. Then, under his breath, "as far as I know."

"And I love him, but he would hate a road trip as much as I would." Percy shot Nico a look. "We're going to visit camp while we're there. Chiron's been asking about you."

Nico turned away from the Iris message and looked out across the sea. He'd been fending off calls from the centaur ever since he'd cut his losses in New York and run. "Yeah, I know."

"He said something about a job opportunity." Percy raised an eyebrow. "It sounded pretty good. I'd take it, but Annabeth has her hands full with the tail ends of grad school and with Nate, we can't afford to move to- shit, what was it?"

"Scotland," Nico said flatly.

"Scotland!" Percy's enthusiasm was wasted on Nico's sour demeanor. "That'd be the trip of a lifetime."

"Yeah, well," Nico crossed his arms. "I've already had one of those. I don't need two lifetimes."

"Give it a chance," Percy said. "You might surprise yourself."

Nico bit his lip, drawing his knees up to his chest like a child. He'd had no qualms leaving his old life behind for the great unknown, but talks with Percy, Annabeth, and Hazel pulled him back to who he was on the eve of his twenty-first birthday, being pulled from a pit of monsters that he thought he'd die in. He was nearly twenty-two now, and he didn't feel any older or wiser.

"Is that Nico?" came a voice.

Percy grinned and shouted over his shoulder, "Yeah! Come say hi!"

A breathless Annabeth came into view, her arms laden down with grocery shopping and the sleeping form of a little boy: Nathaniel, their son.

"Is that Italy? Reliving your greatest hits?" Annabeth wrinkled her nose, inspecting the valley behind Nico. Percy took the groceries from her and she muttered thank you, shifting Nate to her other hip. "I thought you'd have run into some monsters by now."

"Monsters tend to stay away from me these days," Nico said, his mouth sent in a hard line.

"Huh," Annabeth said. Nico could see the gears whirring in her mind. No monsters was worse than a whole horde: something else was scaring them out of the region. "Are you having... fun?"

Nico snorted. "Fun?"

"What? What questions do you want me to ask here?" she shot him a glare. "I'm a mom now, I dote."

"Dote less, mommy dearest," Nico said.

"Hey!" Annabeth objected.

Nico stood, brushing off his clothes. "I better get going. The sun's about to set."

"Stay safe out there," Annabeth advised. She gave him a stern look that pierced him to the core.

"And Nico," Percy said. "Remember what Chiron said. Scotland is pretty nice this time of year."

"Sure," Nico grumbled. "Scotland. See you later."

The Iris message dissipated but Nico could feel Percy and Annabeth's gaze lingering. He attempted to shake it off as he walked back down to the sloping, cluttered village he'd taken up residence in a few months ago. The job offer was nice, but Nico didn't need a purpose anymore. He needed clarity.

It wasn't until the sun had almost retreated beneath the horizon that Nico noticed his wallet was missing. It wasn't as if there was anything of incredible importance in it- just a weathered ID, photos, and a few Euros- but the idea that someone had gotten close enough to him to snatch something off his person was enough to make his stomach lurch.

He thought it might have been the dwarves from Bologna, that they'd flown south for the winter to relieve tourists of every shiny bauble they brought with them, but he decided that wasn't the case when we was wandering the remnants of that day's market at dusk.

Vegetable and fish sellers were packing up wooden pallets and folding tables when a blur streaked through the narrow street, sending Nico spinning.

"Ay!" yelled a vendor as his wooden pallets were destroyed.

Nico's senses went into overdrive, but he hesitated, battling his instinct to chase after whoever it was that had whirled through the piazza like a tornado. He was not a hero anymore, his days of crusading were far behind him- or, at least, he desperately wanted them to be. But he felt something familiar and comforting on his tongue: the taste of adventure.

Nico set off after the runner, his heart pumping in his ears. The sound of his shoes hitting the cobblestones reverberated along the empty village streets, making the person who was running that much harder to find. He couldn't tell if they were behind him or in front of him, but Nico let his instincts lead him through several winding paths.

He exploded onto what seemed to be the main street of the town and managed to catch the tail end of the runner. Nico's eyes weren't the best, but he saw a small bag dangling from their wrist and in their hand several wallets, one of which looked suspiciously like his own.

Nico tore down the street, keeping the thief within sight as best he could, but whoever they were, they were fast. Either that or neglecting demigod training was beginning to take a toll on Nico. He'd thought that demigods kept their physical strength and fitness as a godly trait, but that didn't seem to be the case here. Children of Hades weren't the most athletic of specimens.

He managed to head the thief off at a fork in the winding streets. They collided in a flurry of motion, Nico's hand grasping their collar. A few wallets fell to the ground.

"Who sent you?" Nico hissed. He observed the thief, an unassuming man with oily skin and drab features that almost rendered him featureless. He had to be in his mid-thirties at most.

The man squirmed in Nico's grip, regarding him with a stricken glare, then pulled a piece of wood out of his pocket. Nico ducked, thinking it was a knife, but was surprised to find him point it at Nico's hand instead. Short red flames burst from the tip and Nico dropped the thief's collar in pain.

The thief dashed off down the street again.

"Hey!" Nico called out after him.

He began picking up speed, the burns on his hand making it useless for any sort of fighting, but he didn't think his Stygian iron sword would do much in this instance. The thief wasn't Greek, but he wasn't completely mortal either.

"Stop!" Nico shouted, knowing the futility of the word as it left his mouth.

He willed his mind to stop recalling other missions that were similar to the foot chase he was on now. Running wasn't Nico's specialty and thinking of monsters just made him nauseous. He was lucky the thief wasn't something more sinister, but he already was a mystery.

Nico caught up to the man just as he began to wave his weapon into the air. Nico reached out his hand and grasped a fistful of the man's jacket and heard a sound he'd never forget.

The loud crack of disapparition.

Nico was spat out onto the hard wooden surface of a table and went sprawling, his hand gripping the thief's jacket so forcefully it must have warped the fabric. The pair knocked over two beers, three glasses of wine, and several dishes half-filled with what looked to be a type of pie before they skidded to a stop.

The thief went over the edge and fell onto the floor, much to the surprise of Nico, who lost his grip with a yelp. When he attempted to run again, Nico shoved him up against the stone walls and twisted his arms behind his back.

"I will not ask you again," Nico growled. "Who sent you?"

The thief whimpered and relinquished all of the wallets in his possession. They flopped to the floor anticlimactically. "N-no one! No one sent me!"

"Wrong answer. Try again!" Nico shoved the man into the wall even harder. "Was is the Romans? The Greeks? Did that stupid fucking school in Scotland send a stupid fucking test?"

The thief's face was beginning to bleed from being scraped against the stones. Nico threw the man to the floor where he lay, gasping.

"We didn't, Mr di Angelo," said a voice to his right. "But it worked out just the same."

Nico turned to see a woman who looked old and somehow ageless at the same time. She wore long, flowing robes embroidered with green thread and a black pointed hat atop her head. Nico thought it had to be some sort of costume.

"Thank you for apprehending Mr Hartford, here," the woman said, her gaze turning to the thief. "He broke parole and has been causing quite a bit of trouble for witches and wizards throughout Italy. The Ministry will be happy to know he's been brought in."

"Uh, right." Nico nodded warily. Now that the chase was over, he wasn't quite sure what to do with himself. His breathing was heavy and the burns on his hand began to sizzle in pain. He didn't want to risk shadow travel after whatever magic the thief had cast. "Is that all?"

"No, Mr di Angelo, that is most definitely not 'all.'" The woman regarded him with a hawkish, yet familiar gaze. It was like being reprimanded by Annabeth when he was younger. She turned to the side and spoke to a group of people sitting at a long table parallel to the one Nico crash-landed on. "Aurors, if you would escort Mr Hartford to the Ministry, that would be much appreciated."

The group at the table looked to be at the end of their meal, tankards and glasses nearly drained. If they were any sort of police force, Nico couldn't tell. They looked mismatched and haggard, like runaways or pick pockets, and ran the gamut of an incredibly old man with skin the colour of the earth to a young wisecracker with a shock of blue hair.

"I still think if we hadn't sent in bait, he'd have shown up," the young one said, handing a red-haired man nearly two decades his senior a handful of dirty silver coins. "That's all I have on me."

"You still owe me a full galleon, Teds," the red haired man grumbled. He counted the coins briefly and stuck them in his pocket. "But I'm the master of luck. No use going up against a professional guesser."

The two stood with the tiresome feeling of routine and bent down to pick up Hartford. The one called Teds tapped him on the nose.

"You didn't run fast enough, mate," he said with a rakish smile. "Good thing Potter wasn't here."

They pulled Hartford onto his feet, cuffing him with some sort of gleaming metal, then nodded to the woman. Hartford struggled weakly.

"McGonagall," the red-haired man said. "Always a pleasure."

"The same to you, Mr Weasley." She inclined her head. "Do give your wife my best."

"This one better be worth it," Ted said, indicating Nico with his head. It felt impersonal and alien, to be talked about as if he wasn't even there.

Her smile was light and secretive. "I think you'll find that Mr di Angelo is more than capable. Even more so than your father."

"Fat chance." Ted scoffed. "See you around, Professor."

The two left with their prisoner.

Nico stepped back, still working on catching his breath, as the scene before him unfolded. He couldn't wrap his mind around what had happened in the last few minutes any more than he could tell where he was. For the first time, he took stock of his surroundings and found himself to be in a dimly-lit pub of sorts. The walls were decorated with framed, moving photographs and an odd mix of taxidermied animals. It was then that Nico noticed every single eye in the bar was on him.

"Professor McGonagall," she said, her hand extended towards Nico. "Headmistress of Hogwarts."

Nico let out a sigh through gritted teeth. "I told-" he lowered his voice, suddenly aware of who could be eavesdropping. "I told Chiron I did not want the job. That still stands. What's with all of... this?"

McGonagall pressed her lips into a thin line, dropping her hand that he'd refused to shake. "Come with me, Mr di Angelo. We have much to discuss."

McGonagall led Nico up a set of stairs and into what appeared to be a hotel room, but it was unlike any hotel he'd ever stepped into. The curtains were moth-eaten, the bed sturdy and old. The hardwood floors underneath his feet buckled and warped at the oddest of moments, leading him to feel like he was walking on the back of an enormous toad. It looked more like a room suited for the era when he was a child than a modern one. He was sure even his mother would call the decor old-fashioned.

"Sit," McGonagall said as she settled herself into an overstuffed armchair next to a fireplace filled with embers.

"I prefer to stand," Nico replied, crossing his hands in front of him.

"That was not a suggestion, Mr di Angelo." She fixed him with a stern glare. He reluctantly complied, tapping the spot where he kep his Stygian iron sword hidden underneath his shirt. She set about fixing a cup of tea and dropped two sugar cubes into the cup with a satisfying plop! "I am pleased to see that Chiron somehow managed to contact you about the position we have open at Hogwarts. I hear you're a hard man to get a hold of. Tea?"

Nico stared at the teacup with apprehension. Judging by McGonagall's earlier behaviour, it wasn't a smart idea to refuse anything she offered. He took the cup quietly and set it on the end table next to his chair. "Thank you. Chiron is..." He searched for a word that would be more flattering . "...persistent."

"Yes, that he is." Her eyes sparkled with a sort of mischief he didn't think people her age were capable of. Nico guessed that McGonagall procured a number of staff members this way: shanghaiing them into service. "He's worried about you."

"He shouldn't. I'm an adult, I can do whatever I like." He crossed his arms over his chest.

"Does whatever you like include disappearing for an entire year without contacting anyone?" She sipped her tea. "If so, that was rather irresponsible of you."

"I contacted people," Nico said. He struggled to keep his voice to a normal level. "And the circumstances of my... retirement are none of your concern. Did you drag me to whatever this gods-forsaken place is just to lecture me?"

"This is the Leaky Cauldron, a favourite haunt for witches and wizards in London," McGonagall explained. She glanced about the room. "The decor isn't my favourite, but the tea is lovely. Nearly every student of Hogwarts passes through this pub to prepare for the school year ahead. What I want to know, is if you will be joining us or not."

"Joining you?" Nico nearly laughed. "No way. I did my time, I'm done with school."

"Not as a student, as a teacher," she replied. "Our Defence Against the Dark Arts professor retired two years ago after over a decade of service and we managed to get an Auror to teach last year, but he had to return to the field. We'd like you to educate the next generation of Hogwarts students."

Now Nico really did laugh, long and loud, but without any humor. "Oh, this is rich. You want me to teach a bunch of brats how to defend themselves from the 'dark arts?'" His expression turned stormy. "I am the dark arts."

McGonagall set down her teacup, her hands sure and steady. "I do not know if you are aware of this, Mr di Angelo, but the wizarding world suffered a great tragedy not too long ago. A war swept through much of Europe and decimated our society taking many people that our community held dear, including some of my closest friends. I heard the godly world experienced a similar battle."

"Two." Nico swallowed thickly. "We had two wars."

"Do not hide from your society because of what you did during times of terror and strife." McGonagall intoned as if they were having the most casual of conversations. "Running, while physically a talent of yours, does not seem to be your strong suit emotionally."

He swallowed a snarl that threatened to erupt from his throat. "I am not running because of what happened in the wars."

"Suit yourself," she replied. "But if you are going to abandon the godly world, you might as well do some good in another. Our children know nothing of war, and I pray they never do, but if they must learn I'd rather they learn from someone who knows what the dark arts truly are." She picked up her cup and took a dainty sip of tea. "Or are you not a true son of Hades?"

Nico leaned back in his chair and sighed. "Goading me will not work, McGonagall. I'm not going to work for your magic school- I can't even do magic."

"That can be arranged." Her glance was inscrutable.

He wasn't sure what it was about him or his history that made Hogwarts want him so much. He wasn't the strongest of fighters or the most quick-witted either. He would have thought that they'd go after Percy or Annabeth before they even considered him. There must have been something very wrong with their school if they couldn't even procure teachers within their own world. But then, Nico thought of the war that she said they had fought. The existence of wizards didn't surprise him in the slightest; there was always a stray follower of Hecate or two that wandered onto Camp Half-Blood's radar. If the wizarding world really was as small as he believed, so secret that even most demigods didn't know about it, it's possible that most of the candidates for the position had died.

Nico knew that she could sense that he was struggling with the decision to take the job and laid a hand on his.

"It's time to stop running, Nico," she said, her voice wise and sure.

All of a sudden, he was struck by how childlike he felt in her presence. He had missed having a stable home, someone to care for him. He'd felt that back at Camp Half-Blood and the tiny mess of an apartment he shared in Brooklyn until one year ago. His heart longed to be a part of something again and he could feel it, beating like a racehorse inside his chest.

He took a deep breath. "What do I need to do?"