Uchiha Sora's visit to Orochimaru had yielded quite a haul.
Not only had he successfully obtained the secret technique behind the Cursed Seal and learned where White Zetsu was hiding, he had also happened upon Sasori of the Red Sands, killed him, and acquired the Third Kazekage Puppet along with Sasori's flesh and blood.
Both were important materials that could be used for Impure World Reincarnation.
The Third Kazekage Puppet was a Human Puppet, so it was bound to contain the Third Kazekage's DNA. Likewise, the flesh and blood from Sasori of the Red Sands had to be remnants of his original body.
But he did not have enough White Zetsu Clones at present to reincarnate both of them.
His most pressing task was therefore to find White Zetsu first.
Following the directions Orochimaru had provided, Uchiha Sora soon found an underground cavern.
The cavern lay within his own Land of Grass, right along the border with the Land of Rain.
White Zetsu had been created by the Demonic Statue of the Outer Path, but in truth, he had originated from humans whose chakra had been drained dry by the God Tree over a thousand years ago.
White Zetsu Clones were numerous and remained hidden underground year-round.
After locating the cavern, Uchiha Sora entered alone and began his search.
The underground cavern was extraordinarily deep. Only after descending for more than an hour did he finally reach a natural subterranean hall.
Clusters of White Zetsu Clones were sheltering there.
At a rough glance, there were at least several dozen of them.
According to Orochimaru, White Zetsu Clones usually hid beneath various parts of the Shinobi World to gather intelligence.
These clones were currently processing intelligence they had collected from the surface.
When they discovered Uchiha Sora's intrusion, they all panicked.