Madara kills Obito... But when

[Rikud0 Sennin]

Theories?

Personally, i think it happens after Sasuke visits the Elders of Konoha, and gets some information...
But then he searches for "Madara"~Tobi. He was the other assasin durring the massacure.
Sasuke goes to Him for answers after the village elders. And when Madara learns of Obito killing the Uchiha, he kills Obito, and takes Sasuke in.

 

[Negative Knight]

Nah, Madara would probably approve the Uchiha Massacre.

 

[oShux]

Nah, Madara would probably approve the Uchiha Massacre.

Remember, at OP Madara was pissed off that the Uchiha's turned thier backs on him so he probably wouldn't have gave a shit

 

[~Puppet Master~]

Obito is willing to die using Rinne Tensei, Sasuke doesn't even know of the project.
So I doubt Madara would kill Obito just because of the Uchiha massacre, since they can just be revived inside the infinite Tsukuyomi.

 

[Resurrected Orochimaru]

Remember Obito was pretending to be Madara, and copied his mannerisms and mindset so well that most of the shinobi world believed he really was Madara. That said, more than likely the real Madara would have done the same thing in annihilating the clan.

 

[iKaras]

Did Madara question the lack of Uchiha's on the alliance? Or just doesn't care regardless...

 

[narutoblitz]

Madara probably had a hand in it. It's implied in the backstory he wanted revenge on Uchiha for betraying him. He seemed to think his brother made the sacrifice for no reason, because they sided with Hasirama and exiled him.