A hellish of training

"Again." The High Ranked Demon ordered the younger half-demon as he approached him.

Usopp obeyed, knowing what might come if he didn't comply. He took the sword that was laying on the floor. His hands were shaking, he looked at the impassible demon, and attacked. The sword clashed with another one. The fight continued. Usopp dodged an attack, rolling back on the floor, he stood up and swung the sword. His assault was blocked by the long dark blue sword. The High Ranked Demon allowed a smirk to appear on his face as he attacked his young charge. He didn't give him enough time to react. Usopp managed to stay on his feet as he stumbled to the back.

"Flak'r." He spoke as he suddenly appeared behind the young half-demon. Usopp screamed as he fell on his knees, blood spreading from his cuts. "You've progressed, perhaps against someone of your level, you'd see how much progress you have made."

"Why do I need to learn how to weld a sword?" The sniper complained to himself as he sheathed his sword.

"As a member of the Royal Family, you have to learn all the fighting styles." His instructor answered, having heard what the youngster had said. "Come with me."

The High Ranked Demon was actually one of his uncles. It was a tall demon with two green horns hidden by his red hair. He wore a dark-leather cloth, dark green pants, and a pair of gray boots. He was called Viz'giraz. The demon led Usopp out of the training room, through the different corridors. Viz'giraz entered a large room, in which demons were reunited.

"You'll fight them until you knock them out or they knock you out."

Family

His captain had decided to train for two years. Rayleigh, the famous Dark Lord, former first mate of Gol D Roger, had offered to Luffy - and by extension Ace - training. The head doctor of the Whitebeard pirates had asked Tony Tony Chopper if he wanted to gain some useful abilities for healing, the young pirate had immediately accepted. The Spades offered training to Nami. Yassopp, his father, would have offered training if not his grandfather. A portal had suddenly appeared out of nowhere, startling all the pirates. Usopp had immediately recognized a portal of Hell. A troop of demons had walked through the portal. The half-demon had asked the pirates to not say or do anything.

His grandfather had been among the group. He had requested - or demanded - that Usopp come home. At first, he had wanted to refuse, however he hadn't wanted to show his disrespect to his mother's family, and therefore, he had accepted.

He had found out that his mother's soul had been saved. She had been living since that terrible day in Hell by her father's side. Her siblings - three brothers and two sisters - had confronted her during the time they hadn't seen each other. While she couldn't go back to her old life in the world of living because her mortal body had been burnt, his mother still could return to her original world once in a while. However, she was forbidden to use a portal.

Emma-O was his mother's real name.

"How are you doing?" She asked as she sat by his side, caressing his long black hair.

"I'm exhausted." Usopp admitted with a sigh, he leaned towards his mother, enjoying her presence. "And I miss…" He trailed off.

"Oh I know, Shiva, my son. But your grandfather won't let you go until… well you pass the tests. I still haven't passed them…" The sorrowful tone of his mother was awful to hear.

Emma-O still needed to finish her phase to become a full-blooded demon. The accident had left her in a very bad shape, it had somehow accelerated her evolution, but it hadn't helped afterward. Shiva was still a half-demon, he still had his mortal life to live, nevertheless his grandfather was less inclined to let him return to his birth world.

"And you won't pass them." Viz'giraz stated as he walked in the room. He shot a disapproving look at his nephew then he sat down next to his sister. "Father won't let you if you don't prove yourself."

Emma-O sighed. All her siblings said the same thing. How could she prove herself if she couldn't…? She shared a look with her son, he smiled, she smirked, and the other person in the room looked confused.

The ritual

Emma-O led her son to her private rooms - a large apartment located in the west wing of her father's palace. The succubus smirked as she passed past several soldiers. They all looked down, bowing in respect. Inside of her private apartment, no one would hear what they could say.

"There exists a ritual that grandfather, one of the ones you haven't met, forbids. However, as you aren't still an official member of the Royal family, you can do it." Bankina paused, smiling a bit. "If father doesn't want me to prove myself by any means, it means that I need to do it behind his back. The ritual requires a relationship. The best that works is the parent-child relationship."

"Oh. It sounds like a good idea. What do we need to do?" Shiva asked his mother as she pulled out a box from a hidden place under the floor.

Emma-O explained the ritual to him. You need to draw a large circle in a deserted area that provides a large amount of mao - or magic as most humans called it. Then, the two participants in the parent-child relationship need to be at the center of it. Afterwards, you sing a few phrases, praising Sata'r (or Satan, Emma-O's grandfather) to allow the ritual to happen (even though Satan didn't give verbally and consciously his agreement. It permits the half-demons to fully become demons - and that is to lose their mortal side.

The mother-son pair left the palace in secret. They first went to the capital of the Realm of Fire and Lust, passing by a few shops, meeting a few Ranked demons. Then, they left for the countryside. The pair found a few hours later the perfect place for the ritual. It was a large clearing that emitted a large amount of mao. Emma-O drew the circle, having memorized the different runes used in it, and then she activated it with her blood. The pair took place at the center of the circle, they opened their mouths, and it began.

Words flowed the clearing, the magic increased, and the power that the two half-demons had went all over the Realm. A dome appeared around them, created by the amount of power that both possessed, protecting them from harm.

Emma-O became a full-blooded demon as she wanted from the start. For Usopp, it was different. Something else happened. But none of them could say what happened to him.

Afterwards

Needless to say that Iblis was displeased. He had been the first demon to arrive on the scene, he had been followed by a few Demon Kings (later on, the pair learned that they had been paying a visit to Iblis).

Emma-O grinned despite being grounded for a while. Doing a dangerous ritual wasn't something to laugh about. Shiva as his mother's accomplice was also grounded, he was given less free time and more training. Usopp had complained about it, but he had gotten a quick answer from his grandfather.

"If you want to go back to your friends, you'll need to work your ass out." Then, Iblis turned towards his daughter. "And you… will pass the tests since you think you're ready."

Notes

Emma-O - equivalent of Satan in Japanese

Shiva - (hindu) the destroyer

It's been a while, I know. I've a job, less time to spend writing as much I want - since I'm also playing or doing other stuff sometimes. I want you to remember that this is a one-shot series. Not an actual story. But thanks for reading. I've updated War and Hearth yesterday and I hope continuing updating the stories I've still inspiration even though it would every time take a long time.