This is genius!!!
There's a reason for "second sage".
At first, I thought of the meeting between Naruto and the Sage of Six Paths, Hagoromo Ootsutsuki. But then I remembered his successor, his Younger Son, who took his father's responsibility of creating and maintaining peace in the world. The second Sage is the Younger Son.
And now, it's time for him to CHOOSE his successor. And that's NARUTO UZUMAKI.