Most of this will be 3rd Perspective, and maybe some of Percy's POV too, but I just find writing in 3rd person easier.
"Welcome, demigods!" Zeus thundered. (no pun intended) "Congratulations on defeating Gaea. We will now proceed with the reward ceremony." He smiles down at everyone, except for Percy. He just passed over him like he didn't exist. Annabeth clutched his shoulder nervously.
"Although, we have a matter to discuss." He frowned, his Roman form flickering for a millisecond. "Perseus Jackson, come forward." Percy stepped forward, obviously confused.
"What do you have to say for yourself, traitor?" He spat. Percy looked taken aback. Traitor? Did this guy lose his only brain cell in Tartarus somehow?
"Woah, woah, woah." He held up a hand. "What in the Hades are you saying?"
"Don't say my name like a swear word." Hades grumbled from the corner, folding his arms indignantly.
"Sorry. What in the name of Tartarus are you saying?" He corrected himself. Annabeth's gaze wavered nervously between her boyfriend and Zeus.
"You have betrayed us, Perseus." He growled. "You have been a spy for Gaea! Not to mention you have murdered Annabeth's father. How do you plead?" Percy was shocked. He dared to say that? Right in front of his Wise Girl?
"M-my father's dead?" Annabeth said quietly, tears streaming down her cheeks. "No! Percy would never do that!" She insisted, but she looked at him doubtfully.
"Ok, first, don't call me that." Priorities first, always. "Second, I literally helped in the killing of Gaea. Why would I be a spy? And third, why would I even think about murdering my fiancée's father??" He gritted his teeth, holding back his rage. As much as Percy would've loved to boil his golden god blood right then and there, he held back.
"Liar!" Zeus screeched, pointing his Master bolt at the angry demigod. He shot a glare at Apollo. He looked just as shocked as everyone else in the throne room.
"Dear, how about you think this through?" Hera murmured gently. "Surely Perseus didn't—"
"Silence!" Thunderpants roared. Percy rolled his eyes.
"Did you somehow lose part of your brain in Tartarus?" He asked innocently. "Because you know my fatal flaw is loyalty. In fact, I'm quite concerned for you now, dear uncle." Drama Queen growled at his witty little comment.
"You will be banished to Tartarus for betraying the Olympians!" He commanded. "You—"
"I saved your godly Olympian butts from Gaea, Zeus." Percy retorted. "Keep your facts straight, will you? I can try to find out who murdered Annabeth's father. In fact, I swear that I will pummel him and send his remains to Tartarus if I ever do find him, which I will, and that will prove I didn't murder Annabeth's dad. Besides, do you have any evidence that I myself did it?" He raised an eyebrow challengingly.
"There was a trident painted in blood." Zeus said scathingly. "No doubt it was my brother's spawn." I looked at Poseidon pleadingly, but his face was set in stone. A mask of emotion. Percy's heart ached. Annabeth gazed at him in horror.
"Percy!" She cried. "Why...?" He scowled at her.
"I didn't do it." He was growing impatient. "I can't murder mortals anyways. Riptide would only work on monsters." When will these idiots understand that loyalty is my fatal flaw? Ugh.
"Enough!" Zeus roared, and his form flickered again. "All those in favor of sending Perseus to Tartarus, raise your hand." Athena, Zeus, Demeter, Hera, Ares, Hephaestus, Dionysus, and Poseidon. Poseidon.
"Dad?" Percy cried out. Poseidon looked at him solemnly.
"I never thought my son would do that." Poseidon shook his head sadly. "I'm sorry, Perseus, but my brother is right." Percy bit back a scathing retort.
"Fine!" He shouted, startling everyone in the room. "Send me there if you must. I have nothing to live for, and everyone here except for a select few are so stupid they'd think I'd betray you all! If you can think at all, that is." He stood his ground, daring anyone to argue.
"No, Percy! You can't do this!" Nico yelled, holding Will's hand. Percy suppressed a smile. He shipped those two so bad. Solangelo for the win! They were made for each other.
The Seven looked at their betrayed friend uncertainly, as if debating whether he was worth it or not. Annabeth had a mini river of tears flowing down her face now. Zeus triumphantly raised his hands, and a giant crevice appeared right below him, and he fell into eternal darkness, with the king of the gods gloating.
I was so tempted to end it here...be grateful I didn't
HEHEHEHE
Flashbacks filled Percy's mind as he recalled his last fall into the Pit. Annabeth was there, but he was here again. Alone. He couldn't bear the thoughts, the memories, so instead he wrapped his concentration over a familiar place.
Damesan's place.
It was cozy and warm and welcoming, not at all like Camp Half-Hell. He opened his eyes and realized he had vapor-traveled there. He embraced the warm memories, and a single tear slipped down his cheek. Damesan had given up so much for his and Annabeth's survival. He wished that he could see him again one last time.
Don't cry, don't cry, don't cry, don't cry...
And then another thought occurred to him.
Nico and Will. They had believed in him, believed that he would stay loyal to Camp Half-Blood and them, and he had failed. Again. He shook those thoughts out of his mind, determined to come back for them and all the people who still had their faith in them. Even if it meant to survive the Pit.
Percy brandished Riptide, his only hope. He searched for the water from the River Phlegethon. He was sure that Damesan had stored a couple jars somewhere. He located the fiery water and gulped down a few mouthfuls. A burning sensation filled his throat, like the spicy ghost pepper sauce he had once on nachos. Only, this was a thousand times worse.
After he recovered from the pain, he felt a little stronger. Strong enough to keep going, that is. He gave his silent thanks to Damesan for storing drakon meat in his little hut. As he cooked his dinner, he wondered how he was going to get out, because obviously, this wasn't the end of him. If he could lift the sky, survive Tartarus, fight Gaea and kronos, he could probably do this.
For his revenge, of course.
He could contact a deity, but that would probably end his short life. He could try to get Tartarus, the Primordial, to help, but he would get disintegrated faster than you could say, 'Help.' He could join the Titans...
No. He couldn't possibly think about that...
...could he?