POV Nico
Nico paced the deck of the Argo II as they flew to the Ancient land of Greece. After they're time in Rome had gone bad he was happy to leave it behind. Rome was a disaster although they discovered the Athena Parthenos, the greatest missing relic in Greek Mythology that held powers they didn't even know about yet; they lost their leaders Percy Jackson and Annabeth Chase. Percy was like the brother Nico never had and now he was gone, just like Bianca. And well Annabeth… she was something. He had always had a bit of a crush on her. The images of their last day in room flashed through his mind; Annabeth falling over the edge to Tartarus, Percy going with her, and himself frozen and helpless in saving them. How could he be so stupid he could have grabbed them and pulled them back up or gotten Jason or Frank. No. He couldn't blame himself. Not right now anyway. Percy and Annabeth were still alive, he knew it so why did he feel like they were going to die? He kept hearing Percy's voice
"The other side Nico! We'll see you there. Understand?
Lead them there. Promise me!"
Those two words, promise me, held so much guilt and regret he wanted to hurl himself off the ship and make it all go away. But he made that promise and he intended to keep it. A voice interrupted his thoughts. It was his sister's.
"Nico" she began, "you alright?"
Every time he saw Hazel he saw his real sister, Bianca. But she was long gone, reborn after a death she didn't deserve. She deserved The Isles of the Blest.
"Nico?" she repeated herself.
"Sorry" he muttered
She knew what was going on "Nico this is hard for all of us. There's no point to just sitting around and keeping it bottled up inside and blaming yourself. Talk to me."
Usually that would be enough for him to open up his deepest fears and regrets but for some reason it just made him angry.
"You want me to talk fine I'll talk" he raised his voice, "Who was the one who was kept captive of the most idiotic giants in history Hazel? Me. Who saw Percy and Annabeth go over the edge and couldn't help them? Me. Hazel all I know is stupid stuff about death. I'm useless."
"Nico I saw them fall too. And you're not useless!"
He interrupted her "No Hazel you weren't the one who made a promise. And you know that wonderful prophecy you guys have? You know that line were it says as oath to keep till final breath. What if that's my oath to Percy? Everyone knows someone's going to die. Why don't you ease their minds by telling them it's me that should help everybody out right? No one cares about poor helpless Nico. Well I'll tell you I don't care about you guys either. The only reason I'm here is for Percy and Annabeth."