A NOTE TO THE READERS OF MY OTHER STORIES: Before you question me, readers of my other stories, no I haven't abandoned them, I'm going to be finishing A Bad Reunion and The Worst monster: highschool pretty soon, this idea just randomly came to my head when I was rediscovering how awesome Teen Titans were because I used to watch it all the time when I was a kid.

Anyways, on with the story:

The Seven of the prophecy and Nico thought the giant war was over…but turned out, it lasted for 4 more years. Mother Earth had targeted Camp half-blood and all half-bloods were stationed there to fight for their home. Now 16, Nico di Angelo was suddenly sent to Olympus for a special task…turned out, with all the half-bloods focused on the invasion, they didn't see all the deadly resurrected monsters that have been let loose into the mortal world…and for some apparent reason, the monsters all zeroed on a town Nico's never heard of…Jump City. Let the epicness begin!

Set during giant war, after Things Change episode, Trouble in Tokyo never happened…so Robin and Starfire haven't admitted their feelings towards each other yet.

Pairings: Robin/Starfire, Beast Boy/Raven, slight Nico/Raven, Nico/Thalia?(Tell me in reviews if you want me to do that), Percy/Annabeth, Hazel/Frank, Piper/Leo, Jason/Reyna.

Hope you enjoy!

Disclaimer: I do not own Percy Jackson or Teen titans.

Please note: Unlike my other stories, I won't put in specific POVs, most of the story would be in third person, though I may change to first in some chapters but I'll put in the person's name as a subheading first.

Chapter 1

"Uncle." said Nico di Angelo as he knelt at Zeus' throne in the throne room of Olympus.

The lord of the skies nodded as Nico stood. No one else was there except for his own father, sitting on a stone visitor's throne and Hestia poking the fireplace with a stick in the corner.

"Your father has told you about the…er…issue, correct?" he boomed.

Nico nodded grimly. The sixteen-year-old hadn't changed much over the past four years, although his hair had grown slightly longer and covered a little of his eyes, he had grown taller and developed more muscles over the years of constant monster slaughtering, but he still wore an aviator's jacket with a black t-shirt with a single skull with green flames around it.

"Yes well, for some apparent reason, they have targeted a mortal city known as Jump City." continued Zeus.

Nico raised an eyebrow.

"Jump City?" he asked.

Hades nodded.

"With all demigods at Camp half-blood, no one is available to kill these monsters"

"You want me to do it?" said Nico, cutting his father off.

Hades glared at his son, but nodded.

"Great, but why did you summon me here? You could've just told me about it." said the son of the dead.

"Because the first monster you're hunting is the Clazmonian Sow." replied Zeus. Nico looked at him, eyebrow raised.

"And you suppose me to kill something that flies?" he said, rather challengingly.

Zeus' eyes narrowed ever so slightly, disliking his decision and the teen's attitude immediately.

"Let. Me. Finish." said Zeus through gritted teeth.

Hades stepped in to, for the first time, help his brother.

"Zeus is going to...grant you powers to help." he stated.

Nico eyed the king of the gods curiously.

"Okay…"

Zeus, sighing and seeing no point into wasting any more time, motioned Nico to move forward a bit, Zeus then clicked his fingers and the throne room glowed brightly, causing Nico to close his eyes. As the light faded, Nico glanced down at himself to look for any changes, but his search was vain.

"Uh… am I meant to feel different or something?" he asked.

"Think about that mortal so-called 'superhero', what was his name? Oh yes, Superman. Imagine you flying just like him." ordered Zeus.

Nico raised an eyebrow, but didn't question as he did was he was told with his eyes closed. When he opened his eyes, he found himself hovering above the ground. Surprised and shocked, he leapt up in the air and crashed to the ground with a loud THRUD!

"Ow…" he muttered.

"So I can fly now?" he asked, trying to stop the growing smile of excitement on his face.

"Not just that." began Hades, standing up and shrinking to human form.

He approached his son and touched his fingers to his forehead and chanted something Nico didn't catch. This time, there was no light, but the room seem to darken a bit as the air suddenly grew colder. Then, without thinking, Nico lifted his hand and a small hell fire erupted from his palms.

"Summoning hell fire is like Percy Jackson controlling water, after a while, it will drain you of your powers, but your powers have been enhanced as well, if needed, you can summon a whole army of the undead, and shadow travel more than 15 times without fainting or even summoning hell fire, but you're not invincible, so you can still be mortally wounded."

A bottle full of nectar and a pouch full of ambrosia appeared in Hades' hand as he handed it to Nico.

"You know the rule of the game, only use it in extreme situations." he stated as a black sword appeared in his hands and handed it to Nico.

"Push that button," began to lord of the Underworld. "and the key of Hades would be activated."

Nico was confused at his father's rather…kind behaviour, but decided not to question him. Hades tapped the sword and it shrunk into Nico's skull ring that his father had confiscated a few weeks ago for unknown reasons, but now he knew why.

"And one last thing." said Hades, as he handed Nico a long black cloak.

Nico frowned at it and glanced inside.

"Lined with celestial bronze fabric." added Hades.

Nico gave him a small smile before exchanging his aviator jacket with the cloak; he also discovered 6 daggers inside the cloak and two inside pockets to fit in the bottle of nectar and pouch of ambrosia.

"And remember," boomed Zeus.

"Under any circumstances, do not tell anyone of your identity unless if it's absolutely necessary, am I clear?"

Nico nodded his head as he got ready for his long task ahead of him.

"Nico?" said Hades as Nico was just barely 2 metres from the door.

"Good luck."

For the first time, Nico smiled at his dad gratefully, before heading out towards the majestic city of Olympus and leaping off the edge, only to stop falling as he began to hover and quickly got used to the feeling of flying.

Don't know why Zeus warned me about not telling my identity to anyone, I mean, it's not like anyone's going to come up to me anyways…oh well…next stop, what was that city again? Oh yeah, Jump City.

The Teen titans were eating pizza at their usual restaurant; it had been a very quiet week in Jump City, no robberies, no super-powered villain attack. And that was what kept Robin thinking. They had defeated the Brotherhood of Evil, frozen every super-villain alive that ever crossed paths with the mighty titans…except for Slade.

"Friend Robin, you are…okay?" asked Starfire.

She was worried about her best friend, always zoning out, he hadn't even eaten any of his food yet. Robin snapped out of this train of thought and gave the Tamaranean princess a small, casual smile.

"Oh yeah, I'm fine, never better."

Starfire didn't look very convinced, though she didn't want to bother Robin anymore and merely turned back to her slice of pizza and squirted more mustard on.

"Yes! Finally!" exclaimed Cyborg as the waiter brought on their last pizza they had ordered, which happened to be Beast Boy's absolute favourite, meatlovers.

The changeling cringed as Cyborg dug mercilessly into his pizza.

"Dude, can you at least keep the dead meat off me?" he grumbled.

"There's this saying in life, maybe you've heard of it, it's called DEAL WITH IT!" said Cyborg, before he continued eating his pizza.

"Well how can I deal with it when you're practically spitting it everywhere?" said Beast Boy, raising his voice.

As Cyborg and Beast Boy began their usual shouting match over pizza yet again, Raven, who had already finished her pizza and was reading, slowly lifted her head from the book, eyebrows twitching. Black energy appeared over the two yelling teen's mouths that shut them up instantly.

"If you don't shut up right now, I swear I'm going to lock you in a windowless room, then, slowly and painfully, I'll—" but before she could continue telling the two about her violent thought, something very large and fast fell from the sky and crashed down on the ground.

"Titans go!" yelled Robin as the five teenaged-heroes leapt onto the pavement and rushed towards the scene.

Thankfully, no one was hurt, but moments after the landing of the first object, something else landed exactly where the first did, shaking the ground violently as car alarms wailed and windows shattered.

As the dust and smoke cleared, what the Teen titans saw next was not something they'd expect. Instead of some spaceship, or a new super-villain, it was a boy, no older than they were. He wore a black cloak with the hood on his head, he held a metre long sword as dark as midnight that was pointed at something below him. Robin looked more closely, and saw that the 'something' was a huge pig; only the pig had 2 large pink wings.

"And next time when I saw stay dead…" hissed the boy breathlessly as he brought the sword down, causing observing bystanders and the titans to gasp.

"…stay dead." he growled, before looking up and noticing the scene he'd caused.

"Oh shit." he cursed.

"Who are you and why did you kill that pig with wings?" barked Robin, birdarangs at the ready as Cyborg aimed his sonic cannon at the boy's chest while Starfire and Raven had their respective powers at the ready.

"It wasn't a pig, it was a Clazmonian Sow." grumbled the boy.

The titans, confused, narrowed their eyes, thinking that it was some sort of sacred animal.

"Then why did you kill it?" asked Beast boy, looking pissed because he'd just witnessed an animal that he could've morphed into being killed.

He looked over at the boy's feet, looking for any traces of a body or blood, but found…nothing.

"Wait…where is it now?" asked the changeling.

"Back to where it's supposed to be." said the boy in a monotone similar to Raven's, in which Beast boy mentally laughed at.

However, before the titans could proceed with interrogating the teen, a voice made them root to their spots.

"Hello, Robin."

"Slade." growled the boy wonder as he turned towards his mortal enemy, bo-staff at the ready.

None of them noticed that the boy had already disappeared into the shadows and had reappeared in an alley a few streets away to watch the show. Robin's eyes behind his mask widened.

"You got a new apprentice didn't you?" he growled, turning towards where the unknown boy was standing a few moments ago, but he was gone.

"No, but I certainly got a new benefactor." said Slade, before he clicked his fingers and 50 or so high-tech robots appeared, surrounded the teens.

The shadows thickened as well, and out stepped 5 truck-sized hounds.

The boy in the alley's eyes widened, so that's where those hellhounds went, he thought. Before, he had thought that this wasn't his fight, but now that creatures he was meant to hunt for had appeared, he would have to step in.

"What…what are they?" asked Raven, flustered that she couldn't remember what they were but swore she'd seen them before.

"Enjoy, teen titans." smirked Slade as he once again disappeared into the shadows.

Robin tried to go after him, but was stopped by those large hounds.

"Hellhounds." grumbled a different voice above them.

The strange boy had appeared once again, sword at the ready.

"You guys deal with the robots, these furry idiots are mine." he ordered, before he began slicing through the creatures of the Underworld.

Robin, obviously not used to being ordered, was about to question, but held the thought as the robots charged at them.

After hard kicks, whacks, punches and being hit with multiple star bolts, only a single robot fell to the ground and exploded on impact.

"Great, it took us 45 minutes to defeat one robot, wonder how long it's going to take us with 49." murmured Robin as the rest of the robots advanced on the teen titans.

"Booyah!" yelled Cyborg as he knocked a dozen of them to the ground with his sonic cannon.

But they merely shook it off and stood up again.

"They're too strong, what are these robots made of?" exclaimed the semi-mechanical teen.

"Celestial bronze." said the boy.

"Stand back." He warned, before plunging his sword into the ground.

"Serve me." he hissed.

The ground shook violently as a skeletal hand shot out of the ground, startling Starfire and she screamed. More came as the first skeleton burst out of the ground, the others following. Eventually, 50 or so skeletal warriors stood in front of the boy, in a mix of army uniforms from different times; from Roman gladiators, to modern day U.S. military. The army of undead saluted at the boy, weapons at the ready.

"Attack!" he yelled/ordered.

The army roared and turned towards the robots, and thus, the battle against skeletons and robots had begun.

As the last skeleton whacked the last remaining robot over the head with the butt of its gun, the titans couldn't hold in their shock.

"How did you do that?" exclaimed Robin to the boy who, for some reason, looked dead tired.

"Do what?" he asked, raising an eyebrow.

"Like, raising the dead and stuff! That was awesome yet creepy at the same time." exclaimed Beast Boy, the earlier issue with the pig forgotten.

"Er…it's a family thing." said the boy, whom the titans still didn't know his name.

Only 3 and a half skeletons remained as they marched in front of him and saluted yet again. The boy nodded, obviously satisfied as he snapped his fingers. The skeletons crumbled into a pile of bones and sunk back into the ground with the rest of the other bones that lay around the place.

"And yet we still do not know of your name." said Starfire.

The boy's lips curved into a smile as a familiar title that ghosts would normally call him popped into his head.

"You can call me…the Ghost King."

A/N I'm aware that some characters are OOC, but I'll try my best to keep them in character in later chapters. One more thing: have you guys seen the House of Hades cover yet? Dammit I can't wait till it comes out. Thanks for reading! :)