Tobi is a creation.... Madara confirmed its not Izuna....
how did madara confirm that it wasnt izuna, he never met tobi.
i still dont know who tobiis put if i had toguess it would be izuna and heres y
1.when tobi was shown the case of the dead madara,tobi freaked which would make sense if it was izuna seeing his dead brother
2.we all know tobi cant b madara,so y did tobi say he was madara, my guess is that izuna knew that his brothers name was more feared than his own and that it would cause more chaos among the allied shinobi forces.
3. if it is izuna then that means hes been alive for a long time, which would make sense as to why "tobi" has a hidden hideout full of sharinganinorderfor him to have that many would show that hes hadto have been alive for quite some time.
4. madara was able to gain EMS/rinnegan before he died but izuna wasonly able to gain mangekyo sharingan(this has been proven in that we have never seen tobi use EMS and it would make sense that he was able to get rid of the amaterasu and use his version of kamui as parts of his mangekyo sharingan also make senses as to why "tobi" had to steal a rinnegan instead of naturally acquiring one.
mind you this is just my guess and reasons why i think its this person but i could b completely, we wont know until kishi decides to tell us