Kabuto maru summons someone and madara freaks out

1st
I was watching through the animes while this one moment got me curious Madara asks kabuto what if he refuses to his deal then kabuto summons someone and Madara freaks out who do you think this is?

I kinda think that madara transfered to Obitos body (i dunno how) Cause he only shows his right eye which is the eye that kakashi didnt take plus maybe Kishimotos giving us a clue by his hair? so i think that mybe its his real body but i dont think its madaras brother because he wouldve KILLED kabuto for the body but instead he just started laughing evily? who do you think kabuto summoned?

2nd
There is a good chance it could be Izuna (Madara's brother). He was said to be at equal strength and skill with Madara and we have been surprised by the manga before with Shisui's eye/background. Not to say that I couldn't be Madara's real body since he is trying to become "complete." MAYBE there is some more to the story of the battle between Madara and Hishirama that will be later revealed that can give us more grounds onto why Madara is only a former shell of himself.

3rd
i think it's madara's real body , or it might be the sage of the six paths but i some what doubt that because madara said he has now become just like the sage of the six paths so why fear him .

i think there is some kind of mystery around madara right now and it will all be revealed in time , to em something just feels missing

4th
I just finished giving you an explanation in that other thread. It seems more realistic expectations are necessary.

Izuna and the Uchiha Ancestor are the only two people who could possibly be resurrected via Edo Tensei that would cause Madara to react the way he did. Izuna obviously by being Madara's younger brother and the one whom he received his Eternal Mangekyo. Even for someone like Madara that would be unnerving also seeing as Izuna was near his equal with Mangekyo and even with Eternal Mangekyo it wouldn't be an easy battle.

If not Izuna then the person who began the Uchiha's will of hatred, the Rikudo Sennin's eldest son. His dojutsu was neither Rinnegan nor Sharingan, but almost a hybrid of the two and who knows the devestation that could be unleashed from this forgotten dojutsu. Only a select few Uchiha probably even know that another dojutsu exists as it is forgotten entirely to most.

I will ignore the Obito Theory for now just view the other reply I made. We can take it further if you still don't believe that the Obito theory has no logic to it.

Don't underestimate Izuna that is the first thing most people conclude. The same happened with Shisui now look and his reputation and the power he had at his disposal. Izuna if anything is much stronger than Shisui ever was and a true threat if he faced off against Madara. Madara would win in the end obviously, but Kabuto and his other resurrections could easily prove a problem.

Madara mentioned he would only weaken himself by combating Kabuto then. It is implied he would still win, but at the cost of weakening himself in the process. You also don't understand Edo Tensei and how it functions. Resurrections can only exist because it drags the souls from the Pure World back into the Impure World at the service of the summoner. Even in your own theory it self-destructs as Madara's soul would still be in the Impure World as it never left and thus cannot be accessed to by Edo Tensei.
Why would he fear himself anyway? No one knows your body better than yourself, so Madara could easily take it out if forced into a position. See how logic defies Obito theories at every corner? It doesn't take much thought just reading a chapter over a few times to gather all the information.

5th