I feel like in some years before he was reunited with Will Nico was like Hadestown Persephone in the Pomegranate Prince AU
—!——!—
Nico: Winter's nigh and summer's o'er / Hear that high and lonesome sound / Of my father coming for / To bring me home to Hadestown
Nico: Way down Hadestown / Way down under the ground
Nico: *has his arm around Hermes* Down here, it's a bunch of stiffs / Brother, I'll be bored to death / Gonna have to import some stuff / Just to entertain myself
Hermes: Please get your cane I am not responsible if you fall.
Nico runs some errands for Hades, and since he got closer to Percy recently, Percy joins Nico to help out and spend more time together. And Nico, even if he's more used to sole adventures, can't be more grateful for his company, because it's awesome to hang out with his good friend and years old crush.
Until one day Percy gets cursed, taking a blow for Nico, and it terrifies Nico out of his mind.
They weren't supposed to get attacked, and now Percy is dying in his arms, all because of him. Nico is so scared he doesn't think straight, so he does the only thing that's natural to him in the state of sheer panic — he prays to his father.
Because Percy, the one he cherishes so much, the one he loves to death and beyond, is hurting and dying, and Nico won't handle another loss, especially one as hard as that.
Hades sees the broken terror in the baby deer eyes of his son and sighs quietly, not finding it in himself to grumble. He takes both of them to his palace and breaks the curse. It's a slow and painful process that more resembles torture than healing, and Nico can't look without crying and yet can't tear his eyes away, as Percy fidgets in the sheets, trying to escape pain, delirious and hurt and scared. Hades remains calm and collected, his motions smooth and accurate, and it provides some resemblance of comfort, some reassurance to hold onto.
Nico, shaking and light-headed as if running a fever, learns to breathe again only hours later, when Hades finishes and cradles Nico in his arms while Percy is finally deeply asleep. The shadows of his father's arms cradling him feel like home.
Hades explains in a quiet soothing murmur that Percy will need to recover, but they can't keep him here any longer, so he'll call Poseidon to take his son home. Then he lets go of Nico and leaves, and Nico slides onto the floor by Percy's bedside, still shaking like a softly flickering shadow, his face tear-stained and eyes hollow. He lays his head near the pillow like a pliant loyal hellhound, listens to Percy's weak quiet beathing, the barely audible beat of his heart, the alive pulse of his soul, and tears up again.
Nico registers the presence by his side, but he hollowly assumes it's his father, so he flinches when Poseidon greets him politely. Nico doesn't make an effort to move away from Percy's bedside, though, he's too exhausted and drained for that. And he can't imagine tearing himself away from Percy right now, not when Percy is so fragile and vulnerable and hurt and he'll be fine but he isn't now, and it should've been Nico sleeping through the pain.
It's Poseidon who offers Nico to come to Atlantis so they won't have to separate the kids, but Nico doesn't really registers neither that nor his father accepting the invitation.
It's also Poseidon who says at Percy's room in Atlantis that Nico doesn't have to kneel on the floor for hours if he can just lie on the bed by Percy's side, surely Percy'd want his friend to be comfortable. Nico's too drained to agrue, so he passes out listening to Percy's breathing.
(Percy recovers slowly but surely, and Nico stays with him for a while, first keeping him company at his rooms, then beginning to explore the palace and the city. Their fathers are just glad their kids are safe and supervised.)
