Hiruzen Sarutobi was the Third Hokage of the Hidden Leaf. After the Third Great Ninja War, he decided to finally step down and let his successor be chosen.
Here are the 5 candidates who were in the run to be made the 4th Hokage.
5. Danzo Shimura
Danzo Shimura was also in the run to be made the 4th Hokage. He secretary helped Hanzo in trying to restrain the Akatsuki, but failed. He did this to claim help from Hanzo himself so that he could become the Hokage. Despite failing to become the 4th Hokage, he ultimately got to choose a candidate for the 4th Hokage.
Later, Danzo would also temporarily be made the 6th Hokage, after Pein’s assault on Konoha.