‘I literally do not understand what’s happening,’ said Will, and he knelt in front of Nico. ‘What are those? She can’t be serious about the whole “children” thing, can she?’‌

Nico swayed. This can’t be real. But it was.

Bob raised his broom. ‘I can destroy them in a heartbeat,’ he said. ‘Just give me the word, Nico!’

But the son of Hades rose quickly, his hands up. ‘No!’ he cried. ‘You can’t!’

‘Why not?’ said Will, his eyebrows stitched together in confusion. ‘Nico, we have to leave.’

‘You know what they are, don’t you?’ said Nyx softly, and she cast her gaze down upon the baby demons at her feet.

Nico looked up at her face.

A fragment of a memory struck him then. He had no context, no details –just a gut feeling that he’d seen this before: Maria di Angelo staring at him like this when he was much, much younger.

‘Cacodemons,’ he said. ‘Cactus what?’ said Will.

‘I told you about them,’ said Nico. ‘That’s what Nyx creates –cacodemons.’

‘Oh, right,’ he said. ‘Her children. Personifications of negative emotions and feelings.’

Nico glanced over at Nyx’s other children.

Hypnos, who could put anyone to sleep in an instant.

Epiales, who had filled both Nico’s and Will’s minds with the most horrible of nightmares.

Nemesis, who was obsessed with retribution.

And now …

‘She made more,’ said Nico. ‘I can see that,’ said Will. ‘From me.’

Will’s mouth dropped open. ‘I’m sorry, what?’

‘You knew without me having to tell you,’ said Nyx. She lowered herself to the ground and contracted until she was just barely taller than Nico. ‘You knew exactly what they were.’

Nico stepped forward, past Bob’s objections, to get a better look at the cacodemons that trailed Nyx like she was leading a parade.

‘I made one from each terrible, dark part of you,’ she said, then nodded down at the closest one, the one with gnarled antlers on its head. ‘Go ahead. Meet your children.’

‘Nico, don’t,’ begged Will. ‘Let’s just leave, okay?’ ‘No,’ he said. ‘No, I can’t abandon them.’

He stuck out his hand.

The horned cacodemon skittered forward, its pupilless eyes glowing. It pressed its nose into his palm and sniffed him.

And memories flashed in Nico’s mind:

Camp Half-Blood. The dining pavilion. Percy. ‘She wanted you to have this.’

The forests outside camp. The pit in his stomach. Jason …

Nico jerked back and fell on his butt. The cacodemon skittered away. He looked up to Nyx, tears in his eyes. ‘What have you done?’

‘I sent you visions,’ she said. ‘As soon as I realized it was you Bob was trying to reach, I knew I had a chance to communicate with you as well … and encourage you to accept your true nature.’

Another cacodemon approached, this one with a single eye like a Cyclops and paws like a wolf. It licked Nico’s fingers.

The lid of the jar. The pom seeds. The loneliness.

‘I knew you wouldn’t be able to resist the call of your worst memories.

That’s who you are, Nico di Angelo. You are a demigod made up of trauma. Your very soul is one of darkness.’

A third cacodemon – the one with tusks – pounced and landed at Nico’s feet. It rubbed its head against his leg.

Percy smiles at Annabeth. Will stares at Paolo’s big biceps.

‘You proved my theory right with every step you took towards this place,’ Nyx crowed. ‘The second you entered the Underworld, our new children were born.’

She knelt and touched each of the cacodemons, naming them as she did so.

‘Grief,’ she said, her hand gracing the demon with the antlers. ‘Guilt.’ That one had legs like a spider, and its touch brought forth

images like Nico lashing out at Percy or allowing Octavian to die.

Sadness was a shapeless blob that showed him Maria, Bianca, the Lotus Hotel and lonely nights in the forest surrounding Camp Half-Blood.

Jealousy was the one with tusks, who reminded Nico of how often he coveted the lives of others.

‘Isolation.’ A cacodemon with one glowing eye sent Nico right back to the jar.

‘Shame.’ A catlike cacodemon with needle-sharp teeth and claws scratched at his leg, and he thought of …

Cupid. Cupid and Jason.

There were many others, but Nico couldn’t handle any more. A rage built in him. Or was it shame? Shame, because every single trauma had been trotted out before him – quite literally – for all to see? Guilt, because maybe, just maybe, Nyx was right? Or maybe …

Maybe his rage came from the fact that she had it all wrong.

Nico pressed his hands against the cliffside, and the ground rumbled. He heard rocks fall behind him and splash into the colliding rivers below.

‘Accept it,’ ordered Nyx. ‘Accept that you prefer the darkness. You prefer suffering. You know it is true! Your own children prove it! Stop denying your nature!’

‘No,’ Nico said simply and without emotion.

He rose. The earth trembled. A bony hand thrust out of a crack in the stone.

‘You have no idea who I am,’ he said.

And then he drew his sword and charged Nyx.