Sort of Hades' POV—
"He's not getting any better." Persephone reported. Hades sighed, pinching the bridge of his nose in exasperation.
"What on earth did that sea scum do to make him fall into a coma?!" He groaned, standing up from his plans of torture for the Fields of Punishment. Persephone looked at a parchment curiously and caught sight of a hallway full of Legos to step on. Reasonable, she guessed.
"It's not a coma, but Apollo said it's about to be." She corrected, running a finger down the dark hallways of the palace.
Hades rubbed his temples, walking down the corridors of his dark mansion. Ever since Percy rescued Hermes and Poseidon from Tartarus and killed Kronos by shoving him into the Sea of Chaos, he had passed out right on Olympus and since then, well, he was still sleeping. But there was a strange restlessness in him, like he was in his own mind, a prisoner.
He certainly knew what that looked like.
"What's going on over here?" He demanded as he stepped into the room where Percy was resting. Apollo and his sone Asclepius glanced up from their work.
"I can't find the source of whatever's making him like this." Asclepius complained, pointing at a pale Percy that looked dead, the only saying otherwise was the faint rise and fall of his chest.
"And he's my kid." Apollo added. "All my kids are awesome, just like me." The god of the Underworld facepalmed, which he seemed to be doing often.
"Are you sure you've tried everything?" He cautiously approached the bed, scanning Percy's lifeless form closer. His face was nearly as pale as one of his children, which was saying a lot. As he got closer, he could hear Percy's ragged and shallow breathing.
"Poor thing." Persephone whispered, placing a hand on his head. "He's been through so much." Hades nodded silently.
"This isn't natural, definitely not." Asclepius murmured, pulling out a blue serum from his bag.
"What isn't?" Nico popped his head out from one of the shadows. "Hey dad!" Hades jumped.
"Neeks, you scared me." He scolded him. "And now I'm calling you Neeks. Great. Apollo, your son is rubbing off of me." Apollo grinned.
"No prob, uncle." He winked. "That's my job." Nico smiled a bit, before catching sight of Percy's bed.
"What the Tartarus?!" He yelped, falling back a step. "What's Percy doing here?! DAD, DON'T YOU KNOW THAT YOU'RE SHELTERING KRONOS RIGHT NOW—" Hades held up a hand.
"Percy killed Kronos, but it came with a price." He said gravely. Nico seemed to pale even more.
"No... don't tell me he stabbed himself in his Achilles Spot! Anything but that." He crept closer to the bed.
"He's fine, son." Hades put a comforting hand on his shoulder. "At least, for now." Apollo exchanged grim looks with Asclepius.
"What do we do now?" Persephone whispered. Hades shook his head sadly.
"We can't do anything for now. Just to hope and make sure he doesn't choke on something or does something stupid in his sleep."
Sort of Percy's POV—
Percy did something stupid.
Very, very stupid.
Even though he killed Kronos forever by yeeting him into the Sea of Chaos, he wasn't dead just yet.
Great. Just great. Why can't I just have a day off from saving the world? Ugh. Curse the Fates. He grumbled.
He woke up standing in a dark room, something you wouldn't experience every day. It wasn't a room, though, more like a void. Every time he reached out, his hand seemed to fade into the background. He huffed. This was ridiculous.
"Hello, Perseus." An all-too familiar voice said behind him.
"It's Percy." He snarled, turning around. "Hello, Kronosome." Kronos rolled his eyes.
"I suppose you wonder what I'm doing here." He smiled serenely. "You thought you killed me, didn't you? But I'm still here. Wonder why?"
"Because you're an evil powerful wizard that split up his soul to stay alive?" Percy said sarcastically. "Honestly, it's obvious. You held onto part of my mind when your whatever-you-have-as-your-soul got out of my brain." Kronos opened his mouth to say something, but nothing came out. Percy smirked.
"Surprised? Of course you are." He started towards Kronos slowly, his face set in an expression of determination. The Titan Lord sneered.
"You'll never defeat me." He growled. "I knew you'd betray me. But then you just had to go and throw my body into the Sea of Chaos. Ugh." Percy raised an eyebrow challengingly.
"Wanna bet?" He held out his hand. "The one who wins gets to take the other's life." Kronos reached out hesitantly.
"Deal." They shook, until Percy judo-flipped him suddenly. Kronos shrieked as he landed on his face with a thump. He chuckled.
"You've got to pay attention, Kro." He grinned as he watched him recover. "I suppose weapons don't count?" The titan groaned.
"No, they don't. This is just hand-to-hand combat."
"Or I could pelt you with blue cookies!" Percy's smile widened even more. "This is my mind. I get to do what I want. Say bye-bye, King I-ate-my-children-whoopee!" A giant stream of water suddenly appeared in front of Percy, splatting Kronos in the face just as he got up.
"Bleurghhhhhh!" He spat water from his mouth. "That's disgusting, what is that stuff?!" Percy shrugged.
"Totally not water." He snickered as a sword, perfectly balanced and Celestial Bronze like Riptide appeared in his hand. "Let's see if your skills have improved." He struck a blow to his side, Kronos dodging skillfully and swinging his scythe that appeared.
"No fair!" He wailed. "I haven't practiced in a while!"
"Sounds like a you problem, not a me problem." He slashed and parried so fast that his sword was just a metallic blur. "In fact, that's good for me. So shut it and let's get to the exciting part."
"You'll never win, Percy Jackson!" Kronos howled as he staggered back. "I'll get you into the Sea of Chaos soon enough. Just wait and see."
"I'd prefer not to wait and get this over with." Percy held his sword at Kronos' throat. "Yield?" Kronos smirked.
"I think not." He held out his hand and time seemed to go backward as Percy jumped backward like he was on rewind. "Never underestimate your opponent, Perseus." Percy's eyes widened in horror as he realized what was happening.
Kronos was twisting time to his own, making the battle tip to his side. He could get Percy unarmed and kill him in a second. Or make him freeze and then kill him. Or even make him unconscious and kill him. There were tons of ways to kill him.
In other words, he was doomed.