Before everything ever happened in the ninja world ,there was one thing that changed the fact that the rikudou sennin was the strongest in the reality was that someone named ryuga took the title as strongest from had been dropped to the ninja the bey never knew anything had nothing to do with the ninja world .he defeated madara uchiha , he defeated hashirama senju , he defeated rikudou sennin. even madara knew not to mess with him.
rikudou sennin tried to stop him but instead ryuga sent him flying to the ground.