At the sea for a thousand years, and at the mountains for a thousand years, breathing the wind and drinking pure water, he passed the training of a Sennin. Enduring it all, he gained the Life Return. Humans are able to, from the hair on their head to their intestines, their toes, even to their most minute hairs, to concentrate their senses and stretch them to their limits, making it possible to control every part of their bodies."
This technique allows one to change the muscular balance of their body by subtly shifting there ki. There are three attributes of this technique are described by colors. The mixture of these three represent what a martial artist specializes in. a certain level of skill is required in order to attain mastery of at least two colors, and to possess all three is almost impossible.
Red: A color that represents attack in martial arts the muscles are highly densified to give user strength and power at the cost of speed. Red users are usually the aggressors, taking on a heads-on approach instead of dodging they punch or kick through.
Blue: A color that represents speed in martial arts. Red makes the muscles smaller and lighter making the user appear taller and thinner. The blue body gives user speed and flexibility at the cost of power. At any rate, he is much more agile in this form, and harder to hit as opposed to the red.
Yellow: A color that represents defense in martial arts. This form has the muscles at there most relaxed state. Since the body is relaxed and loose yellow is best suited for grappling, throws, and submission moves.
Black: a mixture of all three colors, it is said that the being who is able to master all three aspects of life return will be inhumanly strong to the point of being able to completely ignore an opponent. They will have the attributes of all three colors as well as the capacity to utilize them with alarming coordination.
A side effect for this technique is that its usage produces a large appetite
Offensive aspects of this technique includes not only the overall shrinking/enlarging of oneself and others, but head shrinking by restricting neural pathways constructing muscles from contracting or relaxing, changing bone mass or drastically increasing or reducing a body or objects fluid volume while leaving the solid or gaseous components untouched. Such spells when directed against his aura actually strengthen you rather than cause their intended damage.