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Nico doesn’t notice it the first time.
It starts as a tug: soft, almost curious, like something brushing against his ribs from the inside. He’s standing in the woods near Cabin Thirteen, one hand raised, shadows curling obediently around his fingers as bone knits itself together from the earth. A skeleton rises, then another, then a third, their hollow eyes turned toward him in quiet attention.
Useful. Easy.
Normal.
What he doesn’t see; what no one sees, at first, are the threads.
They’re thin as spider silk, faintly silver-black, stretching from Nico’s chest to each of the skeletons. They pulse faintly, like a heartbeat trying to remember itself. Every movement the skeletons make sends a tiny flicker back down the threads.
A flicker that costs him something.
Nico doesn’t notice.
Not until the world tilts.
He wakes up to Will shouting his name.
“-Nico! Nico, hey- hey, stay with me!”
Nico blinks up at a blur of blond hair and blue eyes and too much sunlight. His head throbs like someone stuffed it with gravel.
“…what?”
Will’s hands are already glowing faintly gold, pressed to Nico’s temples. “You passed out,” he says, voice tight. “Just- dropped. No warning.”
“Oh.” Nico frowns, trying to sit up. His limbs feel heavy, like they’re still underground. “Weird.”
“Weird?” Will echoes. “Nico, you were unconscious for five minutes!”
Nico shrugs, wincing immediately. “I’ve had worse.”
Will does not look reassured.
The second time, it happens during sparring.
Jason is mid-sentence, something about footwork, when Nico casually summons two skeletal warriors to demonstrate a flanking maneuver.
“See, if you-” Nico starts.
The skeletons move.
The threads tighten.
Nico drops.
Jason doesn’t even finish his sentence before he’s catching him.
“Okay, no,” Will says later, pacing in the infirmary. “No, this is a pattern. You don’t just pass out twice for no reason.”
“I mean,” Nico says, lying on a cot with an ice pack on his forehead, “I was doing death magic.”
“That is not a reason, that’s your baseline.”
Leo leans against the wall, arms crossed. “Dude, you straight-up powered down like a robot. It was kinda impressive. Concerning. But impressive.”
Annabeth is already thinking, eyes narrowed. “What exactly were you doing right before you collapsed?”
“Summoning,” Nico says. “A couple skeletons.”
Percy frowns. “You do that all the time.”
“Yeah,” Nico says. “Exactly.”
Annabeth goes still.
“…do you always dismiss them?”
Nico pauses.
“…define ‘always.’”
They figure it out the third time.
This time, Will is ready.
Nico is halfway through raising a small army, because apparently “a couple skeletons” had escalated into “seven, maybe eight” when Will grabs his wrist.
“Stop,” he says.
“I’m fine-”
“You’re not,” Will snaps. “Just- hold still.”
Will squints, focusing, not on Nico’s injuries, but on something deeper.
And then he sees them.
“…oh,” Will breathes.
“What?” Percy asks.
Will doesn’t answer immediately. His gaze tracks from Nico to the skeletons, following something invisible.
“There’s…something connecting them,” he says slowly. “Like…threads. Energy. They’re pulling from you.”
Nico blinks. “Huh.”
“Huh?” Will repeats. “Nico, they’re draining you!”
Nico looks at the skeletons, tilting his head.
“…didn’t know it did that,” he says. “Neat.”
Will makes a strangled noise.
After that, they try to manage it.
They really do.
Annabeth suggests limits. Percy volunteers to help keep count. Jason offers to train with him in controlled bursts. Leo tries to build something that beeps when Nico’s “life battery” gets low (it explodes once, which is not encouraging).
Will, meanwhile, hovers.
“Nico,” he says for what feels like the hundredth time, “you have to dismiss them when you’re done.”
“I do,” Nico says.
“You forget.”
“I don’t-”
From across camp, a skeleton wanders aimlessly into a strawberry patch.
Nico sighs. “Okay, sometimes I forget.”
It becomes…normal.
Not good. Not ‘fine.’
But normal.
A camper will be heading to lunch and find Nico sprawled in the grass, pale as marble, breathing shallow but steady.
“Uh- Nico’s down again!” they’ll call.
Someone fetches Will.
Percy usually shows up too, already looking annoyed and worried at the same time. “Dude,” he says, crouching beside him. “Again?”
Annabeth checks his pulse. “He’s stable. Just drained.”
Leo peers over. “We really gotta install that warning system.”
Jason stands nearby, arms crossed, scanning the area. “How many did he summon this time?”
Someone inevitably spots a skeleton or two lingering at the edge of the woods, still faintly tethered.
“Three,” they’ll say. “Maybe four.”
Will pinches the bridge of his nose. “Of course it’s four.”
They dismiss the skeletons.
The threads snap.
Nico wakes up a few minutes later.
Every time.
It’s always the same.
A sharp inhale.
A wince.
A slow blink as the world comes back into focus.
“…ow,” Nico mutters, pressing a hand to his forehead.
Will is always there. “Headache?”
“Yeah.”
“Dizzy?”
“A little.”
“Any other symptoms?”
Nico considers. “…regret?”
Will does not laugh.
Percy folds his arms. “You scared everyone. Again.”
“I didn’t mean to,” Nico says, sitting up slowly. He looks around at the small crowd that’s inevitably gathered. “I’m fine.”
“You passed out,” Annabeth says.
“I got better,” Nico points out.
“That’s not the point.”
Nico frowns, genuinely confused. “I don’t see what the big deal is. I just…ran out of energy.”
“Because you forgot to disconnect from the undead you summoned,” Will says tightly.
Nico glances toward the woods, like he can almost see the threads now that he knows they’re there.
“…huh,” he says again.
Will groans.
The thing is, Nico isn’t careless.
Not really.
He just…doesn’t experience it the same way they do.
To him, the threads aren’t dangerous. They’re fascinating. A side effect. A connection. Proof that his power is doing something deeper than just raising bones.
Sometimes, when no one is watching, he focuses.
And he almost thinks he can feel them.
A faint pull.
A whisper of something shared between him and the dead.
It’s not unpleasant.
It’s just…there.
Will finds him like that once.
Standing still in the shadows, eyes half-lidded, a single skeleton idling nearby.
“Nico,” Will says carefully, “how long has that one been up?”
Nico blinks, snapping out of it. “…not long.”
Will looks unconvinced.
“Dismiss it,” he says.
Nico hesitates, just for a second.
Then he sighs and flicks his hand.
The skeleton collapses.
The thread snaps.
Nico sways.
Will catches him before he can fall.
“…okay,” Will says, voice quieter now. “New rule. No more ‘just one more minute.’”
Nico leans against him, eyes closed. “…fine.”
“You say that every time.”
“Yeah, well.”
Nico opens one eye, faintly amused despite the exhaustion.
“Didn’t know it did that,” he murmurs. “Still kinda neat.”
Will presses his lips together, somewhere between exasperation and worry.
“…you’re unbelievable.”
Later, when Nico is asleep, actually asleep, this time, not unconscious, Will sits nearby, watching the steady rise and fall of his chest.
Percy leans against the doorframe. “He okay?”
“Yeah,” Will says. “Just tired.”
Percy nods, glancing at Nico. “…he’s gonna keep doing it, isn’t he?”
Will sighs. “Probably.”
Percy huffs a quiet laugh. “Figures.”
There’s a pause.
“…we’ll keep finding him,” Percy says finally.
Will nods.
“Yeah,” he says softly. “We will.”
Across the room, Nico shifts slightly, brow furrowing as if he can still feel something tugging at him, even in sleep.
Invisible.
Thread-thin.
Unbroken.