Board Thread:Theories and Speculation/@comment-44437908-20200507033747/@comment-3568954-20200521042730

there is no proof that they transmigrate the instant the next generation are born, transmigration is different then reincarnation. reincarnation is the transference of the soul upon death across time and space into a new body, the new body doesn't have its own soul but possesses the soul of the past LIFE. in transmigration, a transmigrant is just the current host of someone who has previously died. a transmigrant possesses their own soul, the older soul is just hitching a ride and influences the current body's soul. so in this case chakra migrated not the soul. when indra and ashura died 1000 years ago they moved onto the pure land. their chakra remained and periodically latches onto(or as naruto explains it, haunts) one of their direct decedents. its likely that neither Indra or ashura truly awakened in naruto and sasuke until they started to embody personalities more closely to indra and ashura