Board Thread:Boruto Discussions/@comment-34938099-20180619182027/@comment-25122992-20180619183830

If we're speaking about the inhabitants of Earth, then it's surely Hagoromo. If we're speaking about all known Rinnegan users, then it's very hard to judge, since Ootsutsuki clan members Kaguya was already familiar with (most noticeably, Momoshiki), posseessed a Rinnegan surely before Hagoromo ever did. It appears to be a power connected to the chakra fruit of God Tree, while we can assume that Ootsutsuki found a way to use chakra fruits a long time before Hagoromo was even born.