It was filled with Muzan's understanding of Natural Energy.
Natural Energy was a very broad concept. Even in the world of the Hokage, there was no profound understanding of it. They merely absorbed it blindly, then used that power.
The first person to study this energy was Orochimaru. He had also used the Cursed Seal to achieve Sage Transformation.
"Orochimaru should have some information on it. Once I leave Mount Myoboku, I can slowly study this power."
However, Muzan had discovered one thing: places rich in Natural Energy would cause certain changes in the environment. It could be a dense forest, or it could be thick fog stretching across the sky.
"In other words, there are subtle differences in the Natural Energy of different environments."
Muzan had inferred all of this from experiments. Although he had never visited the other two sacred lands, he had heard Orochimaru say that both were noticeably different from the Shinobi World's usual environment.
All experiments were built upon bold conjectures. Now, Muzan needed to slowly summarize them, then verify them.
Gamabunta, who was in the lake, saw him standing there in a daze and thought he had turned to stone. He suddenly leaped up, sending a huge spray of water flying. Muzan noticed the shadow overhead and looked up just as a towering wave came crashing down.
He hurriedly used Earth Release, barely blocking the splashing water and keeping it from soaking his experimental notes.
He quickly packed away his belongings and looked up at the massive body before him.
"Mr. Gamabunta, keep it down next time you make a move. Your splashing water nearly ruined my experimental data."
"What a strange little brat."
Gamabunta did not know Muzan was Orochimaru's disciple. He thought Muzan was Jiraiya's new student and wondered why Jiraiya had