Originally Posted by el_deevil
I'm theorizing the jutsu Izanagi+Izanami will be the bridge to the infernal SG jutsu eternal darkness which offers nothing but blindness.
I rather sure a whole new doujutsu which is the combination of Izanagi and Izanami will have side effects, but no blindness. Remember sasanoo had the physical effect of draining the body when over used which took life away from the user inevitably. However, over time kishi relaxes the side effects of haxxed jutsu to the point there is no side effects as we have seen now with sasuke use of a full complete sasanoo without even breaking a sweat much less his body physically being damaged from use of the jutsu.
By kishi's pattern we can easily imagine that kishi will relax if not take away most of Izanagi and Izanami's side effects as the manga goes on by some means.