"Glug!"
The white tubes coiled across the ground like giant snakes suddenly bulged. A massive surge of chakra poured into Madara's head as if feeding, then flowed through his limbs and meridians, gathering near his heart and abdomen.
A steady succession of dull, rumbling sounds echoed through the cave. Through the gap between his fingers, he stared with his right eye at the root, which had swollen several times over.
Sitting casually on the ground, Madara knew that the chakra of the Demonic Statue of the Outer Path and the Dragon Vein flowing through these tubes was forming a close connection with his body.
As the cycle repeated day after day, he keenly sensed that his body seemed to be unconsciously absorbing Natural Energy.
It hadn't produced the toad-like transformation seen at Mount Myoboku. Instead, it had reached a strange balance.
The Natural Energy balanced within his body was condensing into Senjutsu Chakra.
He didn't give it much thought.
Madara immediately fixed his gaze on the Demonic Statue of the Outer Path, standing silently in the cave.
The God Tree, combined with the Dragon Vein, had made him start to question the relationship between Hashirama's Wood Release and the God Tree.
An indescribable, stabbing pain flared in his right eye, jolting him awake. This time, it was more intense than ever.
The swelling pain in his optic nerve made him feel as though his entire brain would be consumed by the flames. Even the extraordinary healing ability he'd gained from the Hashirama Cells seemed to have stopped working.
Enduring the agony, he pulled out a Kunai and used its surface as a mirror. He opened his tightly shut right eye and looked at its gleaming blade.
His eye had already transformed into the pattern of the Eternal Mangekyo. In the