[fatestaynight] King of fire

Secrets hidden in fire

Y/n walks around his new home a giant piece of land taken by his new dad as a prize in the last holy grail war. This uniquely magic-filled area is called einzbern castle. He walked through halls with beautifully painted glass windows, a walking stick laying firmly in his hand. He's struggled to walk since the incident, it's like his body is trying to adapt to a new change way too fast. Causing the rest of his body to fall behind. As he stumbles through the hallway, he begins to think about the last few days.

The fire, meeting their new dad, being told he has a serious case of amnesia and meeting his new older brother. Their new siblings always felt off to him. Like they were hiding something from him and not doing a very good job. It was only little things, for now, Illya's weird looks, Shirou not being capable of looking him in the eye. But he chose not to pry, he just got here right? It's not his place to investigate and try to find out their secrets.

But what soon changed everything was a conversation he was soon to overhear.
"Illya! I still don't understand why we need to keep the magic world from y/n" Shirou asked Illya not wanting to keep secrets from his new brother. "
Look, little brother, out in the wide world loads of magus's wouldn't hesitate to kill y/n and he has no way to defend himself without magic circuits!"
"So it's far better he just doesn't know. Not attracting other magus to come to take his life."
She scolded her brother without any idea who was sitting around the corner.

As his siblings left he pondered on the word magic and what it meant and then suddenly! Memory's rapidly flew through the young boy's mind, memory's that feel foreign and yet he knows in his heart that they belong to him. Memory's of the church he grew up in. Memory's of being taught by his father a burial agent before he died. Memory's of the day of the flames and his desperate attempt to save his own life by establishing equilibrium with his soul.
And then his rotating origin began to speed up. Rapidly it spans, It Span, IT SPAN. Like an endless force, his origins rapidly became one causing a magical influx comparable to that seen in the age of the gods in his body! Throwing away his walking stick as his hair became grey and his eyes gained a Heterochromia with one eye staying gold giving out a sense of calmness and tranquillity. while the other became a very dark red, giving out a feeling of power and mass destruction.

"I'm still alive?"
He asked no one
"After all that my body and soul still fight on with great power."
"Truly, truly amazing."
He walks into a strange shed at the outskirts of the einzburn grounds looking around he places a sign on the outside declaring that this is his room and no one else is allowed to enter.
He sits down and begins experimenting with his new origin knowing that the most important thing right now is to get a good hold on his capabilities.

Using a part of his origin he created the holiest fire possible and forced it to form a construct in his hands. A group of black keys formed between his fingers far more powerful than any that came before. Using the iron plate technique taught to him by his first father he threw the keys at a straw dummy he had left in the centre of the room. When it made contact with the dummy, it burst into the holiest flames imageable causing the entire dummy to be "purified."
Nothing was left as it was all a "human construct" and therefore something that needed to be purified.h

Tests like these are what he did for many weeks. Slowly beginning to distance himself from the rest of the family. This did make his mother Irisviel sad as she desperately wanted a nice family together. But that didn't stop him after all he was a magus through and through. Things like family would only get in the way of his real duty, reaching the root.

In fact if not for the einzburns castle having great mana and interesting research on the third magic heavens feel, it's unlikely he would ever be near them again. Leaving to look for inspiration for his magecraft. And it's nature as an infinity destructive force.