Thread:Silver-Haired Seireitou/@comment-4080775-20150128164634/@comment-2089817-20150128170527

The truth is, there's very little possibility of making a totally unique story for acquiring Rinnegan, because there's only one concrete way of getting it: acquiring Hagoromo's chakra. So you might need to just go on ahead with the idea of absorbing chakra from Yoshitsune, but keep in mind that even with the chakra, Rinnegan does not manifest automatically unless it is from the purest source.

For example, Madara only had the remnants of Indra's chakra, since he was his transmigrant, and whatever chakra from Asura he obtained from Hashirama. Those are hardly pure sources, and this fact was reflected in that Madara only obtained Rinnegan after reaching an extremely old age. Sasuke, on the other hand, automatically awakened Rinnegan in his left eye because he obtained chakra directly from Hagoromo. So, since Yoshitsune isn't exactly the "purest of sources", you'd have to also factor in that it wouldn't manifest instantaneously. And might need some kind of emotional trigger.