That means that Madara got Harashima abilities(DNA) in order for unlocking the rinnegan which he acquired right before Madara died.
Kabuto only amplified his edo body and abilities in order for him to also use Mokuton release like he did with Yamato and that big harashima plant that produced extra Zetsu bodied for the war; or like Orochimaru did for Danzo in order for him to control all the Sharingans on his arm...
don't you remember a familiar face on Danzo's shoulder just like on Madara's chest???