Here it is.
Tobi is madara, the unknown person in the coffin is izuna.
They both had EMS (they exchanged eyes) fearing that izuna would become stronger than him and also knew his plan madara killed izuna and took his eyes. This would explain why madara was afraid at first but was ready to fight kabuto if he did'nt tell him about IWR because he had the rinnegan. How about thisxd
Tobi is madara, the unknown person in the coffin is izuna.
They both had EMS (they exchanged eyes) fearing that izuna would become stronger than him and also knew his plan madara killed izuna and took his eyes. This would explain why madara was afraid at first but was ready to fight kabuto if he did'nt tell him about IWR because he had the rinnegan. How about thisxd