Board Thread:Naruto Discussions/@comment-3965545-20161228130925/@comment-25122992-20170105223818

It's not an anime only. Hagoromo clearly stated in the manga as well that he bestowed his power to Asura before his death, anime just repeated it. Although manga didn't clarify what Hagoromo really meant by the "power" he granted to Asura, anime events don't contradict this case at least and thus are acceptable. Hagoromo mentioned it as the contrast to the situation of Naruto/Sasuke where he gave his power to both of them, while during his lifetime he bestowed it only to a single son (Asura).