He studies the book

Danzo, being cautious, studies the rock and makes sure that it is not a trap by his enemies. But there are strange carvings on top of it. He gets some of his trusted subordinates and have them analyze the rock.

"Danzo-sama, the rock is carved with a seal that we do not know of. Its strength is unfathomable but is weakened by time. The seal is in fact so old it existed for at least one hundred million years. The weakened seal is then finally broken by you." His subordinate replies him, after they managed to put the rock back together.

The Root leader sends his people away, and he looks at the book hidden in the box. It is written in strange, incomprehensible symbols. But when he senses the book with chakra, his eyes widen.

He grunts in pain as all sorts of knowledge rush into his brain.

This is a book written by a priest of some unknown ancient deity, a god known as the Black Goat. It is sealed up by people in the ancient times of this world, and he just freed it from the seal. He gains all sorts of mystic knowledge, and his wild ambition of being the Hokage, no, the King of the World is emboldened by his newfound strength.

He now has a plan in mind...