Underground.
After separating from Uchiha Madara's Wood Clone, Black Zetsu remained where he was. He immediately spread his Sensory Ninjutsu to its limit, then used mental communication to summon White Zetsu to his aid at once!
Beneath the Pentagram Realm, Houka also remained in place. Seeing that Black Zetsu was not fleeing, he sneered and immediately formed Hand Seals, using an Earth Release ninjutsu to force open a vast underground space nearby!
The underground space was roughly the size of a football field and pitch-black. Black Zetsu stood silently at its center.
"Black Zetsu, after stirring up trouble for so many years, it's time for you to rest."
Houka's two Mangekyou glowed with a faint red light. The black-and-red Pentagrams within them resembled two lanterns beside the gates of hell, bearing down relentlessly on Black Zetsu.
"Uchiha Houka, how did you learn of my plan?"
Having confirmed that White Zetsu was rushing this way at top speed, Black Zetsu could not help asking, "Did that immortal old toad tell you?"
The toad he meant was the Great Toad Sage. Back then, the Sage of Six Paths had learned sage arts from the Great Toad Sage. Only after successfully mastering Natural Energy could the Sage of Six Paths touch upon the principles of all things, fuse Natural Energy with Tailed Beast Chakra, and pioneer the Six Paths Sage Art.
If the Great Toad Sage had not taught the Sage of Six Paths sage arts, the Sage of Six Paths would not have mastered Natural Energy. Without Natural Energy, he could not have created the Six Paths Sage Art. Without the Six Paths Sage Art, the Sage of Six Paths could not have sealed Kaguya Otsutsuki!
From that perspective, the great toad of Mount Myōboku was the true unsung hero who had