Combine my excerpt with your fanfiction.
And imagine, Clarisse, Will, Travis and Conner, Pollux, Katie and Annabeth wake up and they are surrounded not only by those who should be in the underworld and what they lost in the first war, but they are also told that the child who defeated the Minotaur is in the infirmary.
Ethan Nakamura wakes up in a crowded cabin number 11, in a familiar sleeping bag on a familiar floor. Next to him, a voice too similar to Mitchell Harris is talking about a child who appeared only yesterday and has already defeated the minotaur.
Percy Jackson wakes up on the sheets that have become so familiar, and the cold of the underworld, which has already seeped into his bones, is rapidly disappearing. Ethan's outstretched hand and Charon's rocking boat on the waters of Styx are no longer there.
What will happen next?
Ooh that's hard, I could see a lot of different things happening because in this Percy died, he was dead and gone. That is absolutely going to do horrible horrible things to everyone around him, and of course himself.
See here's the thing about Percy, he's never activity searching for death, but as long as his friends, his family are safe he doesn't need to make it out alive. And in this it worked. He sacrificed himself, camp won. He doesn't see a problem with this, but his friends...
None of them are going to let him out of their sight because at this point he is no longer their fearless leader, untouchable, unstoppable, practically on the same level as the gods themselves. Percy died, they watched the light go out of his eyes, burned his shroud. He was their friend, and no more a god than the rest of them.
I could see Annabeth and Clarisse especially being all over him, and refusing to let Luke go anywhere near him. Which is very strange to anyone else that is looking in. This random kid somehow managed to unite these two very different people who as a rule are at each other's throat.
Ethan's a hard one, I have to admit I haven't played around very much with his character. But I know he's bitter, bitter at the gods, bitter at his mom even though he adores her more than he should. To have to do it all over again? I'm not sure what he would chose, how he would be able to look at such an unscarred version of Percy.
(And yet, isn't ironic that in fact Percy is more messed up than Ethan will ever know. Because he was dead long before Percy fell into the darkness that even the eldest of the gods feared. The boy he was when Ethan died for him no longer exists, drowned in sulfur and poison and the need to survive.)