After Itachi's 'Ghost' moment with dear old little bro I don't see Sauce becoming a villain when Madara and Obito are both holding the title and happen to be Uchiha. Madaras plan is to pew pew a Tsukiyomi on the moon and that does all of squat to solve Sauce's issues. Why would he join forces with them?
I fully expect Obito to be knocked off by Madara in a display of power, Bee gets taken out of commission somehow, Naruto is left 1v1 with Madara and then Sauce+1 (beefed up with Orochimode) comes in with the Vegeta-esque "I'm not here for you or Konoha, I'm here for me." culminating in a battle that ends with Naruto victorious and Sauce riding off in the sunset to rebuild the Uchiha clan now that Madara and his ambitions are finally dead.
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