Long, long ago....

Feudal Japan suffered an infestation of Yokai, supernatural beings who mostly hunt humans for food. As though it wasn't dangerous enough, a sub-clan of Yokai known as the Makamou terrorize the countryside with their ability to utilize a more powerful gigantic form. Even the strongest and bravest samurais, ninjas, or even sorcerers could stop them. But hope was all but lost.

The originally savage and brutal ogres known as "Oni" offered to teach a new way to fight the Makamou to a farming village. Skeptical at first about the sudden offer the Oni made, the Shogun that ruled the village eventually accepted the offer. The "fighting style" the Onis spoke of was strange, new, but was too familiar to the villagers; it involved music.

After seeing the simplicity of the fighting style, the Onis formed three schools, which eventually grew into entire clans:

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  The Hibiki Clan is probably the oldest clan to exist. Members of this clan use percussion instruments such as drums, gongs, and tuning forks. Their main weapons are a pair of drumsticks and a miniature gong that expands on an enemy and amplifies the impact it receives from the drumsticks. Hibiki Clan members make use of the element Fire and their fighting style is more on upper body strength and endurance. unlike the other clans, they only use the old instruments.
• 
  The Ibuki Clan use aerophones (whistles, flutes, etc) as their main instruments, but eventually welcomed trumpets and similar instruments. The clan consists of good-looking people who are master actors, deceivers, and spies. Along with the Zanki Clan, the Ibuki Clan members can turn their instruments into weapons; usually guns, daggers, brass knuckles, and even a blow-pipe. Ibuki Clan members use the element Water.
• 
  The Zanki Clan, or the "tough guy" clan as the Ibuki Clan calls them, is almost as old as the Hibiki Clan. They use chordophones like the koto, the guitar, and the harp. Due to the new age, the Zanki Clan also use electric guitars, which suit their main element: Lightning.

After almost a century of fighting the Makamou, the legendary Oni Warrior Kabuki (see right), was able to seal the Makamou away in the Spirit World, where they originated. With the disappearance of the Makamou, the Oni Warriors trained new ones in case the Makamou return. This went on for generations, until now.

The Makamou have found a way to destroy the seal made by Kabuki, and little-by-little they escaped. A new Kabuki has sensed this, and also sensed of the return of an evil greater than the Makamou. Under his orders, the three clans must resurface to fight the Makamou and protect the humans, as their ancestors have done so long ago. However, they must do this in secret, using their oni forms as armor for their human bodies.