Idk if I've discussed anything about this character before, but this guy is a male. His name is Raiguko, and belonged to a clan of swordsmen (I guess samurai, since they use a traditional sized katana and wakizashi), and his ancestor wanted to become a demon in order to kill the monsters that were roaming around the world the time he was alive. To do this, he did Baki/DBZ levels of physical training and martial arts training, becoming the 2nd strongest man in the world, the first being a bakuto based on Zatoichi (the primary inspiration for this guy was Fujitora), but becoming strong didn't satisfy him. He wanted to manipulate fire and have the transformation of a goat-horned exposed fang flaming eyed demon, and also be able to produce armor made of a substance that looks like bone but it's not, kinda like the Hollow armor from Bleach. He also wanted to blow steam out of his nose, primarily for intimidation, propel himself either forwards or upwards using the fiery energy, kinda like a rocket in a way, and manipulate his body temperature by making his own body hot enough to burn someone when they touch him.
This guy was once a regular person, but then he did something to achieve these powers. How can he possibly achieve them?