idk what his trump card is either but it could have something to do with with either forcing obito to revive him or something to do with the other uchiha there...its probably the former rather than the latterObito alive due to Senju DNA. Senju inclusive of Black Zetsu (Madara). Madara can now easily control Obito as he is no longer the Juubis Jinchuriki.
Kakashi and (exhausted) Obito could try; but they would fail miserably.
Edo Madara wins low diff
EDIT: What the heck was Madaras trump card!
Hahaha, what are you stupid or something? Tell me one famous ninja that was beat by this kamui? Obito failed to get strong ninja with it, he only managed to capture noobs, who don't have lots of experience or formidable skill. Madara is well informed about kamui and has seen it being utilized countless times during this war, to think Madara has no way around it is laughable at the least. Kamui would be childs play.kamui solos edo madara
Yep, always had that idea in mind. Obito will redeem himself by helping the alliance.