Prolouge
It was almost Midnight when a lone figure appeared out of the shadows into the corner of the cabin in which Nicos bed stood, but the loud noises outside didn't seem like they would stop anytime soon. It wasn't surprising, after all Yule and Christmas were only 3 and 6 days away respectively. But Nico couldn't bring himself to care. Not when today marked the 4th year death anniversary of his older sister, Bianca di Angelo.
While everyone at camp had been decorating for Yule and singing songs around the fire, Nico hab been spending his time in a forest clearing. After the labyrinth incident he had placed a stone decorated with Rosa Fair Biancas (A/N: an English rose. It is short shrub forming fully double, fragrant, pure-white flowers). It was a grave in a way. He came here every year on 18th of december to mourn her loss and to connect to her. He felt at peace here. It was quiet. Not even birds came here, which was surprising, considering that the clearing was beautiful and fulfilled every living condition. It had plenty of plants and fruits that could be used as food, a river coming from the north, flowing into the south for water, and shadows from the trees around the clearing. Nico was sure he even saw a cave in passing once, but he hadn't paid much attention to it.
At least the risk of Biancas grave getting destroyed was low with no animals around.
Nico had spent the whole day at the grave, telling Bianca about his year, even if she wouldn't hear it, considering she had chosen to reincarnate into a second life. But he did it anyways. There was a small seed of hope inside him, that maybe, just maybe, she would still somehow hear him.
He told her about the Argo II, about Leo, Piper, Jason, Frank and Hazel, about the great Prophecy, about the second war and about Will. He told him about how Jason had easily accepted him, how he was his first real friend. His best friend. About the sacrifice Leo had made to end the war. About how he had stood horrified, not being able to do anything as he felt Leo pass into the afterlife. He had kept talking for hours, even when it had started raining.
Nico faceplanted into his pillow with a groan. No negative thoughts. He had already cried enough today. He turned his head to the side a bit, opening his eyes. He was plagued by thoughts for a while longer, before his eyelids fell shut slowly. He didn't even bother to change his clothes. They were still wet, but he was too tired to care.
And with the timing only a god would have he felt his skull ring burn against his skin, without damaging him of course. It was a feature of his ring that his father used to summon him. Iris messaging was to expensive over time, even if his father was the God of riches, and it was just less of a hassle in general.
Nico, who was already half asleep took a few seconds to register the burning of his ring. With time the burning got a bit worse, causing him to finally open his eyes, even if reluctantly. He sat up a bit blearily, blinking the already arrived sleep out of his eyes. He sat on the edge of his bed for a few minutes, before he deemed himself awake enough to see his father.
He got up, legs still a bit wobbly, suppressing a yawn and shadow traveled into his father's throne room in the underworld palace, where his father was already waiting, Lady Hecate and Lord Thanatos were surprisingly also present.
"I greet the Lord of the underworld, lady magic and lord death", Nico respectfully greeted with a bow, even if a bit clumsy due to the sleep still not being completely gone.
"Rise." Hades stated cooly and Nico straightened himself. "I have called you here on the request of Hecate and Thanatos. They wish to bestow a quest upon you."
Nico's eyebrows started to raise a bit at this, but was smart enough not to interrupt his father.
This time Hecate spoke up. "Over the past few years, a dark wizard has been causing havoc in one of my pet worlds. I wish for you to help the young wizards defeat him by enrolling into the british wizarding school, hogwarts." Nico obviously knew about the wizards and Hecates pet worlds. He knew about Hogwarts and what was classified dark magic, like his necromancy, which counted as forbidden magic as it interrupted the sleep of the dead. He had met a few wizards in the underworld, and during his travels.
The most remarkable one he had talked to, would be Gellert Grindelwald, or as he referred to himself, the 'dark lord'. From what Gellert had told Nico, he had been defeated by a man called Albus Dumbledore. So why would they need a demigods help this time, when they managed to do it alone 50 years ago? And how was Thanatos involved in this?
He got his answer a few seconds later when Thanatos started talking. "Voldemort, or Tom Marvolo Riddle, his real name, has not only caused Hecate a lot of trouble with his actions, but also me and your father, by creating something called a Horcrux." Nicos eyes widened a bit. He obviously knew about Horcruxes, since he has helped his father a few times with work. It was a horrifying, but also fascinating type of magic to Nico. But also immensely annoying, due to the extra work it caused in the underworld, so he wasn't particularly fond of it. "It is an extremely old, dark and dangerous type of magic-" Thanatos started again, but one look at Nicos face told him all he needed to know. "It seems you already know what a Horcrux is. Spares me a lot of explaining." "We wish for you to enroll into Hogwarts, find these Horcruxes, and destroy them. You should easily be able to sense them, considering they are objects with souls embedded into them. Normally you would need something like the poison of a basilisk to destroy a horcrux, but i am certain that your sword should do the trick too, considering it's properties. I also wish for you to befriend the boy called Harry Potter and protect him if necessary." Hecate explained. "Do not worry about not having magic. All Demigods possess magic, though it is sealed most of the time, with exception of my children. I will unseal your magic for this quest. I sincerely hope you will not use it for anything not related to this quest." Hecate gave Nico a stern look. "I have already handmade a wand for you. 9.7 inches, Blackthorn, hard to make a connection with, but once one is established the wand is as loyal as no other, and Thestral hair as the core, only able to be mastered by those who have accepted death."
Nico felt a bit at ease, knowing that the core of his wand was a thestral hair. He liked thestrals. He had met a few of them in the past, and immediately felt connected to them. They reminded him of himself in a way. Nico kind of felt bad for the thestrals, considering not many people could see them. He always had a bit of bloody meat on him (weird, he knows, but he doesn't really care), incase he meets a thestral.
Before he could say anything else Hades spoke up again. "Go pack your things and then come back. Hecate will then unseal your magic, give you your wand and stuff for school, and grant you the knowledge of the past three school years, as you will arrive at the start of the school year as a fourth year exchange student, and not start from first year. Time will be turned back a bit, since it is already time for Yule, but it will not be much. Dismissed."
All this happened way to fast if you asked Nico, but who was he to disobey a god? (Or three gods in this case) So he just bowed his head before shadow traveling back to his camp half blood cabin and starting to pack, but not without a groan upon the realization that he would not get any sleep tonight.