Board Thread:Naruto Discussions/@comment-26320638-20150422140407/@comment-5936871-20150423015810

@Legion and Bolt Even if by some chance he didn't use Hashirama's cells (which makes no sense). Hashirama still gave Sasuke his chakra, which gave him Asura's chakra. So when he was about to die Hagoromo was able to appear. Since he awakened Hagoromo's chakra due to combining Indra and Asura's chakra in his body.