The Yakan and The Fushoo
Yakan story:After the fall of the bijuu, the world fell into what seemed to be peace at last. However, this lasted short as each nation soon strived to recreate a power similar to the beast. This became known as the race for power.
The race for power, plunged the world into darkness as war's soon broke out. The Land of Water, taking charge of the situation quickly invaded Sunagakure and exterminated them. Kumogakure attacked The Land of Earth which dispatched their forces before the invasion to place. .. Or so we thought.
Upon arrival, the village appeared to be empty. The army travled through the village, searching and checking things out, expecting a surprise attack, but nothing ever came. The people and animals had vanished, However, upon looking through a large abandoned warehouse the came across the only sign of life. It lived in a large body sized capsule, surrounded by a liquid that was assumed to be something other than water. Inside of said capsul, however was small child.
The commander of the army by the name of Reiki Moshi, assuming the child to be a project, decide to utilize it if possible in hopes that it would provide the answer to their thirst for power. Then under the approval of Kage, the commander took the child in and named him Matsu Moshi.
Matsu, was put under closer supervision from Kumogakure's top protective forces until the project was abandoned for classified reasons around the time Matsu went into medical school. He progressed fast and soon became the head of the Medical department at 25. He then began working on a new type of bijuu for kumogakure as tensions between the last remaining villages started to heat up.
He soon developed a method to push the boundaries of one's mind and body similar to the way the 8 gates work. However, he also was able to effect the instincts and the beast like nature of the subjects. This resulted in the chakra to take the form of different animals and cretures as the mind was stimulated in a negative way. He noted that the test subjects experienced uncontrollable anger and aggression and had no affections to other people. Needless to say, Kumo stopped the project and deemed it inhuman. The products and it's creator was then banished to the far reaches of the mountain by the previous Kage.
Needless to say, the projects and experiments continued and the Raikage was forced to end the man's life forever. Many people could hear the screams of dogs that night, and many saw the light glow in the horizon of the battle. However, the only thing we can prove was that the raikage had died and his body was brought back to the village by his men. We only take the men's word when they say that Matsu Moshi died as well.
The Fushoo:It is noted that when Kumogakure invaded Iwagakure, they found only one person. However, the story dates back far beyond that.
After the fall of the bijuu, a man by the name of Jubo realized that the corps of the bijuu could be used as a vitamin to create a stronger person. However, having no funding or support from the village Jubo decided to preform the experiments on himself. By gathering many of what was left of the bijuu, and compressing it into a small seal he could consume a small amount and gain the effects of eating a whole bijuu. This in short gave him great power, but he lost control. All of the souls of the bijuu that he had consumed were fighting with him and each other to take over the body. Thus he created the Hitoride gem. The Hitoride gem help control the bijuu but he soon realized that his one body could not do it alone and needed to another. Thus he killed and kidnapped many people, dragging their bodies and preformed experiments on them. He soon transfered some of his powers into the mass of bodies allowing them to fuse together in a single child.
The child would eventually go ramped and kill out of his control and he realized that. Thus he placed the Hitoride gem over the child at the cost of his own life. He then became deformed and insane and attacked and killed all of the village of Iwagakure just before Kumogakure had arrived. He then removed the stone from the boys possession and sealed it within a mask on his face and left.
Many sitings have been popping up since that day, of masked men savagely killing small villages... but all of which are unknown