Reincarnation

Overview
Reincarnation (転生, Tensei) is a process through which the chakra and will of a deceased individual are reborn in a new living vessel, referred to as a "reincarnate" (転生者, tensei-sha). While the reincarnates of the same individual share some similarities, for example two of Indra's reincarnations Madara and Sasuke awakened the same straight tomoe Mangekyō Sharingan, they are still differentiable by their chakra signatures enough to not be mistaken for one another by sensors. Kaguya Ōtsutsuki was able to use her Byakugan to see that Naruto and Sasuke were reincarnates of her grandsons. In Indra and Asura's cases, the cycle won't start again until both of the current reincarnates have passed away. In certain rare cases, there is a chance that a reincarnate will possess an extreme similar physical appearances with their antecessor, and in that case, their chakra is so similar that they can be mistaken by each other at first sight, even by experienced sensor types.

Known Reincarnations
Asura Ōtsutsuki Indra Ōtsutsuki
 * Hashirama Senju
 * Naruto Uzumaki
 * Madara Uchiha
 * Sasuke Uchiha