Hyuga Kagami was not particularly surprised that Naruto had mastered Senjutsu, but the fact that Naruto had learned it from Ryūchi Cave caught him somewhat off guard.
Though the three great sacred lands of the ninja world were spoken of in the same breath, Mount Myoboku had always been the one most deeply involved in the affairs of the ninja world.
Back when the brothers Hagoromo and Hamura rebelled against their mother Kaguya's cruel rule, the Great Toad Sage of Mount Myoboku had actually guided them from the shadows. It could be said that the birth of the ninja world, and even the origins of ninja themselves, were inseparable from that Great Toad Sage of Mount Myoboku.
Over the following thousand years, the Great Toad Sage had never relaxed its watch over the ninja world.
Especially when the ninja world was on the verge of transformation, it had planted its pieces on the chessboard long in advance. It deliberately created a coincidence, Reverse Summoning the justice-driven Jiraiya to Mount Myoboku, then used Jiraiya to search throughout the ninja world for the person who could determine its future—the "Child of Prophecy," as it called them.
One had to know that Naruto, the true Child of Prophecy, had not even been born at the time!
This showed that Mount Myoboku had always been watching over the ninja world—one could even say it had always been influencing it.
Now, through a twist of fate, Naruto, the Child of Prophecy, had become a disciple of the White Snake Sage of Ryūchi Cave. Given Mount Myoboku's habit of meddling in the ninja world, regardless of whether the Great Toad Sage had confirmed Naruto as the Child of Prophecy, it would urgently seek out a new spokesperson—one through whom Mount Myoboku could continue exerting influence over