Rikudo Sennin and Elder Toad Sage: The Gift of Prophecy
Based on IKSOKRIPS' Naruto Timeline, the Elder Toad is approx. 3000 years old, and probably lived around the time of Rikudo and his sons
Both Rikudo and Elder Toad have the gift of prophecy
Rikudou foretold of a person who would guide the Bijuus on the right path when the time comes
Elder Toad foretold the Child of Prophecy.
It's possible that the Elder Toad Sage and Rikudo Sennin knew each other, the toad might even be Rikudo's contract summon, that's why both of them have the powers of prophecy, thoughts?