'Sion had also said that he wanted to kill Ryner before his true power activated, so he could save Ryner from his fate before he became immortal and forced to walk the desolate and fiery war torn waste lands alone for all eternity. So it could be concluded that "The Solver of all Equations" has something to do with being immortal' - Thats shitty wikipedia. All it has is info upto the end of anime. And anime doesn't even break the ice on Ryner, Solver of all equations or Allpha Stigma. What he has is not immortality. what you stated is simply a speculation based on the last episode of the anime, a speculation which was proven wring in the later light novel volumes. LOLH has a lot more than what was shown in the anime.
He has the power to destroy and disintegrate anything. Even creators of universes or gods could be disintegrated, if Ryner wishes to.
Sage has creation of all things? Ryner has destruction of everything. He'll just erase Juubi and Sage from the plane of existence. Sage can absorb all ninjutsu? The Comb of Elemio was said to be able to negate all magic in DennYuuDen. And Ryner disintegrated it like it were paper.