Obito mentioned in 614 that madara was never thought of an ally, considering he had to have a real corpse. Madara can not be the jinchuriki for the ten tails if he has a edo body. And then obito said "u are at my mercy", then madara smirked(saying in his mind ya sure i am)so thinking that madara is probably gonna try to kill obito but if they fought who would you think would win