Quote Originally Posted by Abdula
The Sharingan also seems to be the only doujutsu that allows the user to turn it off when not in battle and the eye then returns to a “normal” state.
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You can also turn the Byakugan on and off. It's just that their "normal" state is pupilless, in which case, "normal" can be argued. Would one consider an albino normal? It IS a lack of colour pigment in the iris, but that's similar to the difference in melanocytes between races of people. That's considered to be "different", but yet normal.