The Sharingan

In Uchiha Clan, their eye have certain effect skill,it can give hallucination to enemy. The clan of people got such special eye it is because of their lineage. The eye named as Sharingan. The user can transform their eye to sharingan or normal eye as well whenever they wan to. There are few stage of sharingan. First stage is only one dot, second stage got 2 dot, third stage got 3 dot, and 3rd stage is fully growth of basic. 

After growth into 3rd stage, it still can be growth more powerful and higher stage. It is more stronger than 3rd stage of sharingan. Its name is Mangekyou Sharingan. By different of people, there will be different pattern of mangekyou sharingan. Even mangekyou sharingan is powerful, but it will cause to blind after use too many times, it is not perfect. But it could be perfect, by acomplished  certain condition. The user can take over his brother's mangekyou sharingan and combine it with own mangekyou sharingan to be a perfect sharingan. Of course, this will make his brother to become blind and lost his eyeball. That is the price need to pay to get a perfect mangekyou sharingan.