Chakra: N/A (-5 per turn)
One of the 3 great Doujutsu, the Rinnegan has, like the other, the ability to see chakra and the chakra flow of individuals. It also allows the user a great clarity of perception and tracking abilities, although its levels vary from user to user. Dispicted as the eyes of the SO6P, the Rinnegan awaken on Madara Uchiha after he obtained his EMS and implanted Hashirama's Senju cells in himself. Having both lineage from the SO6P allowed him to awake the Rinnegan. When Madara activates the Rinnegan, he seems to not suffer any kind decrease in his EMS abilities in terms of tracking speed, clarity of perception or seeing chakra. Eventually his eyes were bestowed upon Nagato Uzumaki and in him manifested lower abilities (equal or comparable to MS). While Nagato was never able to deactivate his eyes, Madara could switch at will between his EMS and Rinnegan eyes, although he wasn't able to go from 3 Tomoe to Rinnegan directly. Eventually Obito transplanted Nagato's (and subsequently Madara's) Left Rinnegan into himself. By doing so he gained access to both Doujutsu at the same time although losing the ability to deactivate the Rinnegan and as such, losing chakra constantly to maintain it.
Note: Constantly passively active in Nagato and Obito bios
Note: Requires activation (spending move) for Madara bios but remains active indefinetely afterwards if the user chooses to. After having a complete Madara bio with Rinnegan for 1 month, user becomes able to switch between both doujutsu without spending a move. User needs to have activated EMS before and had it active for 1 full turn.