A/N: At long last, here it is, the FINAL sequel of my Seth Hunter series. Thank you all for your patience, effort, and diligence you've put in to reach this point, and all the support you've given for the prequels. This series would not have gotten this far without them and for each of you giving it a chance. As I mentioned in the beginning, this story is my attempt to prove how an OC driven story can be just as enjoyable as stories with canon protagonists. It is a shout-out against Mary and Gary-Sues (OC and canon alike) and those sappy clichés that have turned readers away from OC fanfics. I hope that when you've reached the end of this story, you will be more open-minded towards OCs, the underdog stories of fanfictions everywhere.

The outline has been drawn out, old and new characters will be getting development, and several plot points will be addressed. If you've liked my previous stories, that's great, but this story is where all the REAL FUN begins! To all those readers criticizing the lack of canon divergence in my prequels can finally sit tight, and read what this story has truly got to offer to the PJO fanbase. It's been a long journey getting here, and I will try my best in making sure that journey is worth it.

Just like what I've done in the third part, the prologue is technically a sneak peek of what occurs later in the story. The next chapter will take place shortly after the third part's conclusion.

Disclaimer: I do not own the PJO series. That credit belongs to the one and only Rick Riordan.

Enjoy the chapter.

Prologue: Sign of Betrayal

Percy's hands were shaking.

He stood, shell-shocked, as he first took in the blood trailing down Stygian Iron, and then soaking into leather gloves. His sea green eyes couldn't blink as the assaulter swiftly took out his blood-stained dagger out of Will Solace, who crumbled to the ground soon after, his blue eyes still wide with shock and betrayal. A pool of red soon emerged beneath him as the attacker stepped over the unconscious body, and turned around, facing him straight on. There was something caught in his throat- his mouth was open, but nothing audible came out. His body seemed frozen, his mind paralyzed before he finally acknowledged that what he saw before him, had happened:

Seth Hunter stabbed Will Solace.

Annabeth's screams jostled him into action as another explosion erupted behind them. Instantly, Percy made a dive- securing Annabeth in his arms as a piece of burning rubble crashed onto the pavement. The two of them tumbled and rolled on the ground, and when Percy came to, he saw Seth turning his back, sprinting away and vanishing into the smoke.

He and Annabeth got back up. His first thought was to chase after the child of Artemis and demand answers, but then he saw Annabeth beside Will, who was rasping for breath, still alive but in grave need of medical help. He felt his heart ache when he saw Will's tear-stained face.

He didn't know what he should do.

"Don't move!" He heard Annabeth say frantically to Will. She had taken off her jacket, using it stop the blood flow, and then she addressed him. "Go after him, Percy! I'll contact Chiron. Go!"

Percy didn't need to be told thrice.

He heard Annabeth whispering words of encouragement when he took off, his lungs pumping for air as he quickly ran out of the ghastly wreckage. Police cars have surrounded the war-torn area, and a blockade was being set up as fire trucks and ambulances pulled into the parking lot. Worried parents were hovering over their injured children, and reporters were scrambling to get set up. Percy scanned for any sign of the culprit, until he spotted an auburn-haired teen moving past running spectators.

"Seth!" Percy yelled, and sure enough, the older teen halted just the slightest moment, thus confirming his identity. The two of them locked gazes, his silver eyes unreadable when he started shoving past offended bystanders to get through faster. Percy ran towards the crowd.

He was pushing past bustling people, focused solely on Seth's retreating back until Percy was free. He stumbled a bit before picking up the pace. Cold air bristled against his sweaty face as he pushed his arms up and down, but no matter how much energy he'd put in, the distance between them didn't grow any shorter. Percy knew Seth was a great runner, but he didn't think he was this fast. The two of them raced down the sidewalk before Seth jaywalked onto the street. The lights had just turned green, and it was rush hour. Cars barely stopped to allow Seth and him pass, and numerous collisions followed as a result. Percy leaped over one car, colliding against the windshield before jumping onto another vehicle. He was forced to stop when a truck zoomed by, and when it did, Seth was nowhere in sight.

Percy stepped down on the sidewalk, ignoring pointed fingers and glares as he swerved about. He wasn't about to lose him. He won't lose him!

A motorcycle roared past him, followed by an angry man in a helmet shouting curses. Percy snapped his head back to the motorcycle, his eyes widening when he saw Seth riding it and literally leaving him in the dust.

Something inside Percy snapped, and thinking quickly, he noticed that the streets were lined with fire hydrants. He surged forward, concentrating on the water that laid beneath the city streets. His hands tightening into fists as the nearby fire hydrants exploded. The scattered streams converged and pooled around the son of Poseidon. With a wave of his hand, Percy was lifted from the ground, and like a tidal wave, stormed his way down Lenox Avenue.

He spotted Seth Hunter zigzagging past cars. Percy could hear the number of car accidents and wire lines snapping behind him, and made sure to keep his attention to the front. He didn't want to see the devastation (and casualties) that was inevitably left behind by his stunt; he couldn't afford to get distracted. He would have to leave it up to the Mist to take care of it. Right now, his only goal was to stop Seth from escaping. As for what would happen next...Percy wasn't too sure. Hopefully, he'd figure it out when the time came.

It appeared that Seth noticed he was gaining on him. The engines roared even louder as Seth revved the speed up. Percy strained to maintain his control. He slowly lowered himself down, and when he was close enough, Percy leaped out and locked his arms around Seth's shoulders and neck. Seth gasped in alarm as he lost his grip on the motorcycle, and both of them were sent crashing against the ground. Percy winced as his body gained new bruises and cuts from each tumble, but he still kept his hold around Seth, who hissed like an angry cat and elbowed him hard on the chest.

Percy was forced to let go, but before Seth could get very far, he lunged for his feet. His best friend turned enemy kicked at him, even grabbing one of his dark daggers to swipe at his hands. He was forced to let go yet again, and as he got back on his feet and got Riptide into sword mode, Seth was already running down an alley.

He was in pursuit, his body still feeling the haggard effects of his power display earlier, but he pressed on. Percy saw Seth flipping over dumpsters and scaling the walls to gain an edge in speed. However, when they went down another path, it was a dead end; met with a back entrance of a shabby, abandoned apartment complex with fire stairs too high off the ground for either to reach.

At least, that was what Percy initially thought.

What he didn't expect was for Seth to have this long silvery stick suddenly emerge in his hands, the thing lengthening longer by the second. He saw the child of Artemis spin his new pole of silver, and like an expert pole-vaulter, heaved his whole body off the ground and launched himself up against the fire stairs. With a grunt, Seth successfully grabbed a rail and started going up the stairs two steps at a time. The silver pole he had in his hands had mysteriously disappeared.

Percy knew he wasn't going to catch up to Seth at this rate. So, he did the only thing he could do to slow him down. He ran towards the base and slashed one of the four metallic stands.

With its foundation jeopardized, the whole metal set started to creak and shake. Percy moved out of the way as the fire stairs came tumbling down, Riptide secured in his hand. He watched as Seth scrambled up the remaining stairs as the whole thing tilted and fell sideways. Instead of falling to the ground when the smoke cleared, Percy saw Seth hanging about, his dagger embedded into the wall. He gazed down at him steadily, and then Seth did something unexpected.

He smirked at him, as if amused by what he had done.

Without a word, he brought out his other dagger and stabbed that into the wall as well, making his way up to a third story window slowly through brute force. Percy didn't stay by and watch. He slashed the locks over the back door and shoved his way in. The halls were narrow and filled with a musty odor as he searched the rooms until he found the main stairs.

After lots of running, Percy eventually got on the third floor. He rummaged the rooms, knocking down doors only to find them empty. He entered another room with no success, until he heard a crash in the room across his. He quickly ran to open the door...

...only to be greeted by Seth's incoming fist.

Thanks to his quick reflexes, Percy dodged the brunt of the punch. Seth stumbled from the lack of impact, leaving himself open. He quickly took advantage of that by landing an underhanded punch at his stomach. Seth gasped, and he quickly surged back up and slammed a back kick at Percy's side. The air was knocked out of him as Percy fell forward. He managed to bring Riptide up to defend, but this time, Seth was ready for it.

The son of Poseidon gave a silent scream when Seth kicked Riptide out of his grasp, leaving his hand burning in pain. He heard Riptide clatter on the ground while his eyes struggled to keep up with Seth's continuous onslaught. He swerved his head instinctually to avoid the high kicks, only to get another hit land against his side. Percy leaped out of the way as Seth brought his other leg around, dodging yet another fatal kick to the face as he dropped down into a tumble. Seth yanked his foot out of the crumbled plaster before pursuing after him.

The child of Artemis maneuvered around the narrow hallway effortlessly- leaping up and using the walls to propel himself up for better openings. Percy could barely let himself breathe, much less try to talk sense into his friend, as he guarded against Seth's rapid kicks, who switched between both legs so quickly to aim from the left, right, or center. Percy could feel Riptide in his back-pocket, but Seth wouldn't let him reach for it- he attacked him with every chance he got, purposely making sure Percy didn't have time to draw his weapon. It took everything Percy picked up from his unarmed combat spars against Clarisse to guard against Seth's superior moves. His arms were likely bruised beyond recognition by now, and his sides and calves were sacrificed in favor of protecting his head. Finally, when Seth leaped up, his sea green eyes captured his opponent's mid-air movement and forced his body to arch back. Seth's eyes widened in surprise as his leg brushed the air above Percy's chest, and in that brief second, Percy lunged forward with his fist…

…only to have his fist caught by Seth's hand.

With his hand still caught, Seth rotated his whole body around, anchoring his hands against his outstretched arm to slam both legs against his head. Blood welled up in his mouth as the doubled-force of the impact made his body crash through a battered wall and into a dusty, brightly lit room.

After a couple agonizing moments, Percy forced himself up again. The side of his head was bleeding so profusely that he had to close one of his eyes. His breathes came out erratically, his balance unsteady, and he had a feeling one of his ribs was fractured. His hands fumbled for Riptide, which had returned to his pocket, and he quickly brought it out as Seth emerged from the billowing smoke. The sight of his sword made Seth pause for a bit, his silver eyes staring at his weapon too long to be mistaken for caution. Somehow, seeing the son of Artemis' sudden interest in Riptide made Percy uncomfortable.

Seth broke the silence. "You are quite an extraordinary demigod, Percy Jackson."

The compliment made him tense, and that wasn't the only thing making Percy uneasy. His heart was racing, and his hands shook around Riptide, his bruised fingers and arms not quite healed from Seth's earlier attacks. Most would brush off the feeling as a symptom of pain, but Percy knew better- this was a symptom of fear. He hasn't felt this fear for a long time. He wasn't scared when they went into the Underworld. He wasn't scared when he faced Ares or Clare or Luke. He had felt fear when he met Kronos for the first time, but that fear was...understandable. Kronos was out of his league, and even the gods felt fear at the mere mention of the Titan Lord's name.

There was something about Seth that put him on edge, something that immediately made Percy's instincts scream danger and want to stay as far away as possible, which made absolutely no sense to him. Seth was just a demi- no. No, he wasn't! Seth is a clone of Artemis with no mortal blood in his veins, that's what Seth truly is. He wasn't a demigod like the rest of them, no matter how much Seth claimed to be. Had Percy's considerations blinded him from this fact? Made him underestimate Seth? He had made a fatal mistake- this battle wasn't between two demigods, where Percy could rely on his parentage to tip the scales. He should have proceeded with this fight with caution like he did with Ares, even more so, since he knew Seth wasn't as careless as the war god.

"You know," Seth continued, who started to circle around him slowly, his stance almost a replica of how Artemis approached Atlas before striking- stealthy, quiet, and predatory. "…the last time that move was used, the opponent ended up with a severe concussion and had to be excused from his duties for a week. He was a son of Ares too. To see you stand right back up to face me…" He smiled as he dusted off his shoulders. "Consider me impressed."

"More like you've lost your touch," Percy retorted. Instead of getting defensive, Seth chuckled.

"As always, your witty comebacks are gold," Seth said dryly, and the way he looked at Percy couldn't be mistaken as anything else but awe. "I can see why you get along with him so well."

"With who?" Percy said, puzzled. Seth only stared at him, and shook his head.

"You've got a nice sword there, Percy Jackson," Seth said with a chilling smile, "Riptide, I recall its name was? The sword that can morph into a pen, and return to its owner's pocket. Is Riptide your favorite weapon, Percy?" He tensed when the child of Artemis stepped forward. "You seem to look a lot more confident with that bronze toothpick in your hands. In fact, I can't recall a time you've used any other weapon besides Riptide. Could it be…that you're incapable without it?" *

Percy gritted his teeth, refusing to let Seth rattle him and went straight to the point. "You hurt Will, Seth."

"I did," he said easily.

"Why?" Percy demanded, and Seth sighed.

"I think you know why."

"I know you had nightmares," Percy said, "I know you had trouble sleeping because Kronos wouldn't leave you alone."

Seth frowned, looking displeased. "Thalia told you that, didn't she? She was the only one I confided in about my insomnia."

"Kronos is using you, Seth," Percy insisted. "Whatever he has promised, he's not going to keep it! You need to fight off his control-!"

"Kronos isn't controlling me, Percy," Seth murmured. "He doesn't need to control me to let me know what I desire, or convince me to fight for what I want."

"What do you want?" he demanded.

"Revenge," he answered, "and Lord Kronos will offer me plenty of that, Percy." Then, he stopped and relaxed his stance, placing a hand to his hip while another fumbled at his shirt collar. "I'm sure you'd love it if I stayed and chat with you some more, letting you bide more time for Annabeth and your friends to come get me, but I'm running on a tight schedule. You seem very disoriented, and I rather not see you pass out in front of me.

"So how about we strike a deal?" Seth asked rhetorically, "How about you let me leave freely and chose not to run after me, and in exchange, I won't knock you out to next week? What? You don't think I can do that? Look at yourself- your knees are shaking, you can barely hold your sword. I'm letting you walk out of this, Percy, allowing you to keep whatever pride you have left and end this duel with a stalemate. As your former friend, I strongly suggest you take it."

Former. Seth no longer saw him as his friend. Not anymore. The jig was up, but Percy still couldn't bring himself to believe that the child of Artemis, the first person to willingly accept him after his claiming, the one who fought beside him on Quests and Capture the Flag, the one he would confide his problems to, and the very first friend he made at Camp Half-Blood, would dismiss all that and betray Camp Half-Blood. Betray the gods. Betray their friends. Betray him. All for his revenge against Artemis? It's true that Artemis shouldn't have condemned Seth's old family like that, but he thought Seth was past that when he rejected Luke's offer back then, and when he decided to come on the Quest to save Artemis. He thought Seth favored the company of all his friends at Camp instead of those traitors, who Seth had expressed deep contempt for many times.

Apparently not.

No matter what the practical side of his mind told him, Percy's emotions refused to accept it. "I don't believe you."

Seth mistook his statement. "I make good on my promises, Percy. If nothing else, that part of me has never changed. I won't attack you if you choose to leave-!"

"Not that!" Percy snapped. "I don't believe that the friend I knew would ever turn his back on his friends. I refuse to believe that revenge is more important to you than the bonds we shared! I also refuse to believe that everything I knew about you was faked – I don't believe it!"

Seth stiffened, his countenance less confident and more cautious when the son of Poseidon took a step forward, his sea-green eyes glinting with a new determination that brought strength back into his battered body. "This is your last warning, Percy –You are hurt, and you will not last long against me like this. Return to your friends, and let me go."

Don't make me do this, his silver eyes seemed to plead before the emotion was filtered out again, returning to that foreign cold and calculated gaze. The drastic change left Percy baffled, and that dark feeling that chaffed at his nerves came at him at full force. His instincts were screaming at him to run, to take Seth's offer and never look back, but Percy chose to remain firm.

"If I am to return to my friends like you suggest," Percy began, his hands tightening around Riptide, "then you need to come with me, because you are my friend too, Seth, and I refuse to return alone without a fight!"

I will not abandon you. Not when it isn't too late.

Seth smiled mirthlessly as he summoned a pair of silver knives, his body poised for an attack. "It's unfortunate you can't accept things my way, but I can't say this is unexpected."

Percy smiled back warily, his heart feeling heavier at each passing moment. "What can I say? I'm not good at following instructions. You know how I hate following rules, no matter what good they are meant for."

"I can agree with that," Seth said easily, before seconds later, he moved—

…and Percy's mouth overflowed with blood.

-o-

*Something I noticed about Percy is that he ALWAYS fights with Riptide. We all know Percy is a great swordsman, and as a Big Three kid, his reflexes, endurance, agility, and strength are above average for a demigod, but Riordan never went into detail about his unarmed combat skills, if he had any. In the Camp Half Blood wiki, if you search up Camp Half Blood (heh), there is a picture of Percy's chosen classes/schedule. He did not take any combat classes. In fact, there were no combat classes mentioned in detail in the first series despite the Ares Campers being good at it. Of course, given Percy's animosity towards Ares, it's unlikely he would choose to take a class filled with his kids. So, taking this info into account, I had to imagine how Percy would fare in a realistic fight without Riptide or his affinity over water, which, as you've read, isn't too great against someone like Seth, who is trained in combat and obviously familiar with Percy's fighting style.

I've read fanfics that make Percy too OP or naturally good at everything when the canon states otherwise. Just because he's a son of Poseidon does not mean he is invincible. Combat is just one of those areas I believe Percy is lacking in, and I will be addressing that weakness in this story. Also keep in mind that Seth Hunter is not a demigod. His 'race' (which will be addressed eventually) make him more god than mortal. I also had Percy realized this fact too late because if Percy recalled what Seth truly was, then I dare say the fight would have started out differently.

A/N: Please leave your thoughts, opinions, and/or feedback in your review! Thank you for your patience and I hope this chapter was worth the wait.