Kagutsuchi

Long ago, in the Land of the Rising Sun, there was a disastrous time of civil wars known as the Sengoku era. In the year 1600, this war was brought to an end with the great battle of Sekigahara. During this battle, there was a small feud between two samurai. The one had stolen the other’s love. The other samurai took this battle as an opportunity to defeat this man to claim the woman as his own. His skill, however, was no match for the other. In one fell swoop, the loveless man was knocked off his horse. He lie on the ground with a gaping wound in his stomach as the other proudly claimed victory. This victor went by the name Kosuke Yukimura.
The battle of Sekigahara and the long age of strife ended. The war was won by a general named Ieyasu Tokugawa. Under the reign of Tokugawa, the country returned to a peaceful state and its culture flourished with new life. During this new era of peace, Kosuke Yukimura retired from the violent life of a warrior. He settled down in a small mountain village in the central region of Chuubu. He lived in a small cottage with his wife, Yumi. They had a son named Saki and lived happily for a couple years.
Yumi got pregnant again. This time was unlike the first. She occasionally experienced burning sensations as if her stomach was on fire. When she went into labor, not only was she in excruciating pain, but her entire body burst into flames. Her husband stood by in horror as the doctors tried unsuccessfully to put out the roaring flames. The mother died just as she was giving birth. Her body was so badly charred that she was unrecognizable to her own husband.
The baby, however, was entirely unharmed. He looked like a perfectly healthy child, but something was amiss. When his father tried picking him up, he suddenly burst into flames. Kosuke and the doctors gawked at the child as he cried normally as if there was not fire coming from his body. Despite the flames enveloping him, his body showed no signs of damage from the heat. He was immune to it. The fire was a part of him.
Kosuke had always been a gentle and loving husband and father. He had never laid a hand on Saki, even when the child had made the most careless mistakes. With Yumi’s death and the birth of his second son, Kosuke changed. He blamed the child for his wife’s death, saying the child murdered his own mother. Grief turned this once kind man into a violent monster where his second son was concerned. He mistreated the boy from the moment he was born, despising that such a beast could be his child. He named the boy Kagutsuchi after an ancient Japanese fire deity that was said to have burned its mother to death.
Kagutsuchi, or Kagu, was unaware of his strange ability. At unexpected moments, the boy would catch fire. He did not feel it. It only made him feel a little warm. He could not control it and certainly did not mean to hurt anyone. His bouts of fire were especially sporadic as a baby. When he cried when he wanted something, he would ignite. AS he aged, these fire tantrums became a little less common. It eventually got to a point where the fire would generally stay in a small radius or only flare around a small area, such as his hands or feet. Since the house consisted of wooden walls, paper doors, and straw mat floors, Kosuke had to buy heat-resistant coverings so Kagu did not set the place on fire.
As soon as Kagu could walk, his father had him do most of the work around the house. He treated the younger boy as a slave rather than a son. Saki, however, was constantly pampered and praised. Kosuke beat Kagu for every little mistake he made. His past as a warrior made him all the more brutal. On occasion he would take his sheathed katana off the wall and threaten to use the blade. He was especially dangerous in instances when Kagu’s fire caused problems, since this would remind him of his wife’s death. He tried not to display his brutality around Saki, since he wanted his first son to believe he had not changed. Saki was aware of his brother’s abuse, but his frail physique and pity for his father made him timid to say anything.
Kagu would accidentally burn the crops in his father’s garden, which resulted in the young boy getting thrashed. His father would walk away and continue his day as if nothing happened. Saki would approach his younger brother and try in vain to comfort him. The father fed Saki well while feeding Kagu scraps. After cases such as the garden accident, he would make him eat in the corner, outside, or not at all.