When the Mitsuki Goddess of the Moon fell in love with Eriko the Cat demon they both gave away their immortality to live a mortal life and have a child. When the other Gods, Goddesses and Demons found out about this it was already too late and their worst fear came true when Yumiko was born. The Gods asked a powerful Demon named Lucifer - one of Eriko's brother's - to kill the child and its traitorous parents. Though some of the Gods and Demons disapproved of this saying "It's only a child it has done nothing wrong". They pleaded with Lucifer not to kill the child. He agreed to kill the former Goddess and Demon but when it came to the child he made no promises to kill it. The other Gods and Demons did not like his idea for the child would be more powerful than them. As their fear took a hold of them they argued, while Lucifer watched over the child from the shadows.
Lucifer learnt that the mother of the child died soon after giving birth and the farther wasn't far off maybe a year away. The child Yumiko as his brother called it was smart and developed quickly by one month old she had her flames at the tips of her cat ears and tail that she inherited from her father. By four months she played in the water and could slightly control it as inherited from her mother. By six months she was strong enough to take her first steps, a month after that she could freely walk around. Five more months went by as he watched the small girl grew, he had met with Eriko a few times and discussed her future. Eriko told him that he was not going to last much longer in this world and asked Lucifer to look after Yumiko and take her to the Demon Realm. Lucifer agreed to this deal as he had become attached to the small child. Lucifer had come to the conclusion he would train her in the Demon Realm until the age of twelve.
The day of her first birthday the Gods, Goddesses and Demons had come to a standstill about the situation with Yumiko. Lucifer suggested that he take her to the Demon Realm to train her. When they asked why they should trust her when she finds the truth that they wanted to kill her. Lucifer replied 'She has no reason to hate you or want revenge, or have you forgotten that both her parents have died of natural causes. I will take care of her until her death'. They were shocked to find the Eriko had died just days ago. They agreed to Lucifer's plan but he must start to train her immediately. When they dismissed him he took her to meet the rest of her family. For the next few years he had taught her to control her flames and what he called the Moon's eye where she could control the elements not just water to his amusement. On her third birthday Lucifer had a Katana made he had also given her father's Katana to her as most Gods, Goddesses and Demons had their own Katana's. He decided to teach her hand to hand combat as he did not know how to wield a katana. But soon found a teacher for her to learn swordsmanship. Satan the king himself took an interest in the child and taught her a few defence jutsu's and a summoning jutsu. On her twelfth birthday she said goodbye to all her friends she had made in her time there and asked if she call upon then. They said yes whenever she needed then. Satan and Lucifer told her to go to the village hidden in the leaves as there she will be accepted they gave her one last goodbye before she left. When she arrived she immediately passed out because she was not used to the air pressure on earth. When she awoke she was in a hospital room with people in masks surrounding her. She asked "Who the fuck are these people?"...