Board Thread:Theories and Speculation/@comment-35023081-20190916124836/@comment-38812954-20190916193340

It is an ability of the mangekyou, but after that (being awakened) it becomes a seed of the soul. Urashiki took sasuke's chakra and awakened another rinnegan similar to sasuke in his right eye.

In the case of Obito. I think having an opposite eye (madara's own eye, with components such as his own EMS and the rinnegan) disrupted the spamming of the susanoo for him. With only one of his own original MS eyes I think he'd still be able to spam it.

In the case of Kakashi. he had the eye, but no soul or chakra for susanoo manifestation. As he is not by blood, or descendance an Uchiha. But when Obito's soul did possess him. he did after that.