Ok this really bugging me I've heard a few people say that Minato mastered sage mode and that it said that in manga but then I've heard from most people that he didn't and that it doesn't say that in the manga and I myself don't remember ever reading that in the manga so I'm asking you guys to clear this up for me please can someone tell me for sure he didn't master sage mode because if he did then my opinion on his level of strenght totally changes because sage mode combined with is speed equals him being the strongest ninja in the manga and kinda makes it harder for Naruto to surpass him.