Board Thread:Boruto Discussions/@comment-34938099-20180619182027/@comment-1512913-20180619215200

On Earth it was Hagoromo, elsewhere in the universe/universes, unknown. probably an Otsutsuki even long before Momoshiki. When Momoshiki saw Sasuke with Rinnegan, he wasn't really surprised, so for all we know, Rinnegan might be quite common among the Otsutsuki,