When Horo was born his mother Katina could no longer survive due to the immense negative energy that was breaking her body down daily while being pregnant, so she passed after giving birth. Horo was sent to an orphanage ran by the PCO for his toddler years, but was eventually taken away by a man in a black suit. That man would take Horo to a place that would make his childhood a living hell, but also forge him into something more than a supernatural, something more akin to a hidden calamity.
The man was from a mysterious organization, A place called Silence. Silence was a place not many knew about, and those who did were sure to be silent about it or nonexistent. It was a place that was built into the side of a mountain, mostly black, Temple like, extremely spacious, and was larger than what is seemed due to a spatial expansion technique. They specialized in various things such as information gathering, investigation, research, retrieval, espionage , and most importantly assassination. The training regiment was torturous and outright brutal for a child.
The organization knew Horo was special because they were already investigating his mother, and she happened to be the creator of the transmutation spell. They patiently waited from the shadows and witnessed everything that happened to Katina, and Horo's birth. At the moment of Horo's birthed his body released a blinding black light for an instant and there was something akin to a tattoo and it looked just like a thinner version of the black tree his mother was obsessed with, and later it was discovered that he had black bones excluding his teeth. They waited until Horo was around the age of 5 to take him from the orphanage and to Silence.
The day he arrived at silence felt like the day he arrived in Hell. They began training him as if they didn't care for his life. They had him sleep live in complete darkness for days on end, walked on scorching rocks, threw him in water while tied, whipped him in his back 100 times for everytime he cried, have him trying to dodge wooden sticks while blind folded and much more. Whenever he seemed to get acclimated to whatever torturous training they put him through, they would make them more dangerous or begin a new more ridiculous and painful training.
They trained him like this until he forgot what pain felt like, until he wouldn't make a sound no matter what torture he went through and this was all before the age of 8. After all of that torture true practical training began for him. He began feeding him better than he ever ate in his life, but he only had 1 hour per day to eat and clean himself. He began training in various martial arts that he would later master such as Capoeira, Judo, Muay Thai, boxing, and Jujitsu. He also learned how to properly wield and efficiently use almost every kind of weapon, as well as how to make anything that touched his hands become a weapon. He was taught to always keep a "weapon" on his person at all times. He slept only 6 hours per day he was forced to meditate for 8 hours a day, then was training and learning the rest of the day.
They began letting him truly develop his supernatural abilities at the age of 10. His talent was always stunning, but when he began utilizing negative energy and developing his traits which was found to be his Black Skeletal and "Lightless" Black Eyes. They had no Idea what the Tree on his back was or could do and they found out nothing about it, but Horo knew that it was the reason he had his traits as well as why he could absorb and utilize negative energy so efficiently.
Horo chose to become a dual supernatural, because he was naturally gifted to be a spell caster from birth due to his constitution being partly pure negative energy. He made his soul idol the thing he connected with the most, The black tree that seemed like it had instincts of its own. It was as if the true natural formed a perfect extremely vivid image in his mind and he had already made his core spell the extremely special, one of a kind, transmutation spell inherited from his mother. The moment his soul idol was completely formed it resonated with the tree on his back and formed a connection that seemed to transcend what was known as supernatural, he intuitively felt it was beyond something special.
After being in silence for so long he voluntarily did everything and didn't need to be forced to do anything, he would do whatever he was told as it seemed no one cared about him as a person but an object. . He continued to hone himself and learned about the world. He learned multiple languages, studied everything his mother left behind, created his own fighting style incorporating his traits, spells, and favorite weapon.
When he was 15 and at the refined realm, Headmaster of silence began to sent him on mission as they had had many warriors much more powerful than him so they knew he wouldn't escape. After a few missions he realized every one of them was related to his development and benefits. One mission he had to go and obtain the chain off of a chain coffin that was retrieved from the bottom of the ocean, and then placed in a relic holding site. After completing the mission headmaster helped him merge the relic with his trait "Lightless eyes" in order to complement its known abilities, but due to the purity of his negative energy his trait evolved. Another mission helped him obtain a special treasure called a dimensional pearl, he used this to once again evolve his lightless eyes which took him to the peak of refined realm.