trained how??? whos to say madara was even alive, obviously it wasn't madara who appeared to itachi because the massacre happend after the kyuubi attack which we now know "obito" was the one behind it.
dude growth sprut isn't something u can use to explain his growth in a year or his skill level from being nothing to being able to fight with minato granted he was owned in 1 move to be able to do what he did makes no fucking sense even for a manga.
this is worse than when aizen became immortal and wtf panwed everyone with 1 attack.
the obito who got his ass handed to him by gai is now strong enough to fight gai kakashi bee and naruto all alone and control all the bijju at once..
of course we can argue that him being able to fight on par is simply cause his mks is so fucking haxxed it makes susanno look fucking useless, but still he's able to hold his own.
idk this all seems stupid from a kid who was like naruto to go to being evil as shit why what for...??
i can only say this it will be fine if he was mindfucked into doing all this via madara genjutsu or maybe he had a mind control jutsu placed on him as yura had by sasori.
and it still doesn't explain the fucking height...... no it wasn't a trsnformation jutsu when ur hit it disperses we've seen it happen countless times.