Board Thread:Episode Discussions/@comment-1181222-20171122123506/@comment-35622277-20171122155429

In regards to Toneri, maybe he's the one who's single-handedly holding the fabric of space-time together, hence the immense strain on his body.

Either that, or it could be that he has hidden the part of space Earth inhabits, so as to deter any future Otsutsuki incursion to the planet, but again, probably places tremendous strain on his body.

Those are my two theories, drawn from the cracking-glass style effect that seems appear in front of him, as well as Kinshiki's earlier comments of Space Curvature (which is a theoretical concept of relativity). I had a thread on this a while back - http://naruto.wikia.com/wiki/Thread:239131

Considering Kishimoto wanted to write a new Sci-Fi manga, this concept may have been thrown in by him.

I have a feeling Momoshiki and Kinshiki could deal with Toneri first, as he's still extremely powerful.