Board Thread:Theories and Speculation/@comment-26894845-20151212061943/@comment-25122992-20151213195823

It's not really nessesary to be close descendant of Indra/Asura to become his reincarnation - Naruto, for example, comes from completely separated branch of Senju clan, which even began to call themselves as an another clan (Uzumaki) + only half-related to them (with non-Uzumaki father), yet he's still Asura's reincarnate. At least, Uchiha clan didn't broke into multipile parts with induvidual names and specialities for each of them, thus it's not very hard to conclude Indra's reincarnate will appear only amongst them.