Nidaime
He understands even better now how his friend and predecessor felt when he was trying to get the various ninja clans to cooperate, Sarutobi and Danzo were worth four headaches all by themselves, per day...
For different reasons of course, Sarutobi was simply so brilliant, maybe a bit to scholarly, but that was alright, by his rule they should be peaceful enough for him to use the time to record and create new things that would alter benefit the village.
Danzo though, Danzo troubled him. He was to intense, for all the wrong reasons and calculating to a shameful degree. The boy could not grasp the idea of village first, self last. The Nidaime shook his head, for all his calculating and intensity; Danzo would be his last choice for Hokage.