Board Thread:Versus Debates/@comment-33068632-20170910112454/@comment-734582-20171223155915

Vladosaurus wrote: That's ridiculous...than why didn't it happened the same when Obito did it? Hagoromo says specifically that Naruto (and by deduction, Sasuke) summoned him. Somehow, Naruto unconsciously called out for help (and by deduction, so did sasuke). By Hagoromo's words, Ashura's, Indra's and Kurama's chakra would allow him to come out. Either Naruto and Sasuke briefly shared some chakra (e.g. during Majestic Susanoo), or their combined effort met the requirements (Naruto fulfilling the Kurama/ashura and Sasuke the Ashura/Indra part). Either way works.

Obito wasn't dying and so likely didn't call out to him. By the time he died, hagoromo was already manifested in the Shinobi world. Madara on his deathbed did not have Kurama chakra, so even if he would've called for help (and that seems unlikely), Hagoromo would not have been able to manifest.

it's not until Hashirama touches Madara that Hagoromo can come out, which is weird. But it could just have been a coincidence, since the requirement was already met in Madara. For all we know, he was merely gathering some power in order to manifest, as he'd already given away all to Naruto and Sasuke. Either way works, since whether the requirements were met or not, Hashirama touching Madara would fulfill it anyway. After all, Hashirama was revived with his own living cells which contained Ashura chakra, even if he himself was not a transmigrant anymore.