Board Thread:Naruto Discussions/@comment-26367861-20161025235033/@comment-1512913-20161027015154

Not this again... lots of bullshit all around. Sharingan is noting more than special chakra produced by the brain in an Uchiha. This special brain chakra when it goes into the eyes, expresses as the Sharingan. This special brain chakra is also part/included in Indra's chakra, meaning every single Uchiha's chakra is simply a watered-down/diluted chakra of Indra.

Simply put, all an Asura incarnate needs for the Rinnegan is Indra's chakra, there is no need to transplate a Sharingan.