Danzou Shimura

Danzou Shimura was an elder of Konohagakure. As the founder and leader of Root, Danzou gained notoriety as The Darkness of the Shinobi (忍の闇) because of his frequent unsanctioned actions and his often-suspected (but rarely proven) undermining of specific Konoha personnel. Despite his decades of suspicious deeds, Danzō only ever acted in what he believed were the village's best interests. He was appointed the Sixth Hokage Candidate (六代目火影候補) after Pain's assault on the village.

(Source: Narutopedia)