Board Thread:Naruto Discussions/@comment-28869806-20150430170122/@comment-1783334-20150518185519

Orochimaru lost his parents. Hiruzen practically became a spiritual father for Orochimaru. He loved him like a son. No parent can just bring themselves to kill their own child. As for Danzo, Hiruzen knew you need a balance between light and dark but he wasn't willing to cross over to the darkness so he let Danzo do that instead.

As for Tobirama, if you say me, Madara was a very unstable person at the time. If Tobirama's distrust didn't push him off the edge, something else would sooner or later. If Madara lived with Konoha to the first World War, he would have believed what he read in the Monument, which was edited by Black Zetsu, and would have sought Hashirama's DNA for himself and decided on the Moon's Eye Plan sooner ot later.