I'm bad at writing this kinda thing, but here goes.
Nico's POV:
"Nico! Whatever is about to happen, whatever you've done, I love you. You hear me? I love you." Kole faced the skeletons, barely holding them off with her glowing sword.
"Kole?" Nico stumble forward, almost landing on his face. "What-where are- Did I summon those?" Neither of them noticed Lyssa changing her magic staff into a five foot long perfectly silver sword.
"Nico! Yes! I knew you could do it! And yes, you did raise them. And it might be a good idea to unraise them before they kill us." Kole said uneasily. Nico stomped his foot, and the spartoi shrunk to piles of bones. Kole dropped her sword and ran to him. Seconds before she reached him, she stopped abruptly. Kole's eyes widened and she gasped, slowly looking down.
Looking down to see the twelve inches of silver metal protruding from her stomach.
Nico's sword was in his hand the instant he registered what was happening. Another instant and the goddess Lyssa was in a place where she wouldn't be heard from in a long, long time.
Kole stumbled forward, her hands over the gaping wound in her side and blood spilling between her fingers. Nico caught her as she fell, lowering her to the ground gently.
"N-Nico..." Kole muttered weakly.
"Shhh. Don't talk. I'm gonna get help." Nico tossed a drachma from his pocket through the steam coming off of a puddle of acid on the sidewalk. "Show me Chiron at Camp Half Blood."
A blurry vision of the amphitheater shimmered into view. It looked like they were burning shrouds...Nico ignored whatever he was seeing.
"WAIT!"
He was vaguely aware of his sister shooting to her feet and saying something, but it didn't register. "I'm near Central Park! Look for signs of destruction and send some people here as soon as possible! Kole's hurt and it... it doesn't look good."
The vision dissipated when someone on the other side closed it. Nico turned his attention back to Kole.
"Nico. I don't think-" Nico cut her off.
"No. Don't even say that. You're going to be fine. Perfectly fine. Do you hear me? You've survived worse than this before. Remember the snake king? You can get through this. You have to. I can't- I can't lose you too." His voice broke.
"The Keres...Your hair was sparkly for three days!" she laughed, but it became a hacking cough. Her eyes started drifting closed. Her entire shirt was soaked in blood, front and back. Nico stroked her hair away from her sweaty face, trying to keep back the panic bubbling inside him. He couldn't lose her, not when he'd finally found someone to love, to love him. Not when it was his fault she was here in the first place. She couldn't die, he needed her, he didn't want to live without her, like he used to. What was he purpose of this life, if there was no one to love? Everyone he cared for was torn from him, ripped away and held by the one thing he thought he could control: death. His one strength, his heritage, the palace where he belonged, was the one that took everything he loved.
"No. Don't close your eyes, look at me. Hey, look at me." Nico said, and undertone of hysteria in his voice.
Kole's POV
She could feel nothing but pain, liquid fire rushed through her veins. She didn't want to leave Nico, she didn't want to die. But oh, the pain. Her eyes slowly drifted closed.
Nico's POV
Nico held Kole's limp body against him. "No, no, don't leave me." He whispered desperately. His trembling fingers brushed the hair back from her face. Inches separated girl's deep brown eyes opened and she studied his face carefully. She put her bloody palm against his cheek and pulled him into a kiss. Sweet and soft. When Nico pulled back, her breath was still. Her eyes stared unfocused at the cloudy sky. A sob escaped from him. Nico had never been a crier, he'd always kept his emotions to himself, never let anyone see what was truly going on inside of him. But now, he couldn't stop it. It was all to much to bear. His shoulders shook violently, an endless flood of tears streaming down his cheeks. What was the purpose of it all? She was gone. He wished he was gone. It should've been him, he should be the one cold and limp, not his one love.
No POV
Piper, Jason, Frank, Hazel and the Stolls ran through central park, narrowly avoiding trees as they sped blindly along. They reached a clearing, at the center of which was a cement fountain. Puddles of purple acid dotted the sidewalk and small fires burned through the bushes. And beside the fountain, near the center of the clearing, sat Nico, hunched over the limp form of the daughter of Hermes. Piper's hands flew over her mouth, not able to mask her cry of grief. She dropped to her knees, silent tears streaming down her face incessantly. Jason knelt beside her, wrapping an arm around her shoulders. For once, she found no comfort in his embrace.
Hazel first reaction was relief. Her brother was alive, and well. But then she saw his face. the grief showing in every line of his body. The tears flooding down his cheeks. She ran to him, Frank following a few feet behind. Hazel put a hand on her brothers shoulders, kneeling down beside him. Nico turned from the body before him and leaned into his sister.
Travis and Connor stopped at the edge of the clearing, trying to comprehend the scene before them.
"No. She can't be dead. She can't be dead!" Connor shook his head violently.
"Who did this? Who?" Travis demanded, marching over to Nico. "Nico, who did this?!"
"Someone who's in Tartarus and won't be returning anytime soon." Nico growled, roughly wiping away tears.
?Unknown POV?
The spirit of Kole Evans stood before the judges in the Underworld.
"I rule for Elysium."
"I second."
"I third."
"Judgement passed."
Kole's spirit was sent off to the place where she belonged, the hero's final reward. The place where Nico could visit her.
Nico's POV
They'd burned Kole's shroud a week ago. Nico had disappeared from camp not two days after, leaving Hazel, Jason, and his friends to worry. His dreams were haunted by not foreshadowing visions of death, destruction, or war, but of memories. And that was the most painful thing that could happen.
Finally, after two weeks, Nico shadow traveled to Elysium, in search of his lost love. Alas, she was nowhere to be found.
- Nico's Birthday, two months later -
Nico had finally returned to camp, but he was different. Back to his old depressed, antisocial self. Not even Hazel had seen him smile in two months. It was his birthday, and though Hazel had come knocking probably twenty times, but he wouldn't answer.
"Nico. My son." A tall man in an Italian suit melted out of the shadows in Nico's cabin. "Today is your birthday."
"I noticed." Nico grumbled.
"And I have come to you to present a gift. But there are conditions for this gift. No one must know what happened, and you must not speak of it to any deity. Ever." Hades vanished.
Nico rolled his eyes. "Thanks a lot dad." A knock came at the door. Nico sighed and opened the door and a single tiny neon green grenade rolled through the opening. Seconds later, it exploded into a shower of tiny paper hearts that covered Nico from head to toe. And when he looked up, an enormous smile split his face.
