Their existence is supposedly known only to the Hokage, both Sixth and Seventh, the latter of whom currently leads them, and Akihiko Yamanaka. According to Kasuga, the shinobi world was slowly dying following the end of the Fourth Shinobi World War due to a significant decreasing of the need for shinobi missions; given the heavy decrease in conflict among the nations and even the strangely quiet behavior of bandits and other criminals. It was the Sixth Hokage, Seireitou, that identified the dependence that the villages had on the abundance of missions, as it was their sole source of income and allowed their economy to prosper, and therefore decided upon a solution that would serve the greater good of his land.