Calling it. All of it, right here.
Madara, probably with zetsu's help, saved obito
he trained him
he made him promises that he could revive Rin
and he's been using Obito like a tool for that purpose
Obito doesnt give a shit about the moon's eye plan.
He's doing it all to bring back Rin.(omg no that couldn't POSSIBLE be the reason, or its a dumb reason!) yes it could and no it's not. Read the story of Troy.
Obito has not truly fallen too far, and may still turn on Madara(Naruto has to keep up his ways of changing everyones mind, he's done it with the most extreme cases and doubt he's gonna stop before the finale, and no, Obito is not in the same category as Orochimaru)
In the end, his brother will get to him, and it will be-
Naruto/Sasuke vs Obito/Madara. Obito eventually going good or using his rinnegan(he hasn't used it yet for a reason) to try and revive Rin at the cost of his own life. Everyone turns on Madara. Naruto sasuke have a spar at the end of the series.