Naruto: The Ultimate Mind
The human mind is the most complex organ in the human body. As complex as it may be humans only use 10% of the brains full capabilities. Ninjas on the other hand use in average 30% of the brain, but not always the same zones, depending on individuals and clans. For example the Yamanakas in time gained the ability to read minds and a part of soul projection called body possession. The Aburame in time gained a form of telepathy which lets them communicate with bugs; the same can be said about the Inuzukas. The Akamichi in time gain an ability that can be classified both as shape-shift and transmutation, gaining the ability to enlarge their bodies, or part of the body, but their not able to use it to its full potential, being required a lot of chakra as a medium. The Naras have a high level of intelligence, but sustaining that intelligence requires a lot of energy, thus giving them their trademark lazy attitude, also they are able to use umbrakinesis, the ability to use and modify shadows, but this ability is diluted requiring a lot of chakra. You may say that bloodline are exceptions to this fact; maybe some but not all. The sharingan for example is such bloodline that, when activated, increases the use of the brain to 50% accessing the ability to instantly see and decipher information, thus their ability to copy jutsus, but turning 20% of your brain on and off multiple times creates instability, sometimes causing insanity, uncontrolled emotions or lack their off, and poor judgment. An example of this being Madara Uchiha. So as we can see the brain is a powerful tool but also a dangerous one if you're unable to control it or force it past your current capabilities. But the question remains what would happen if the brain worked at 100% efficiency and capacity?