Board Thread:Naruto Discussions/@comment-30168130-20161009021213/@comment-1512913-20161009170824

Well, here is the thing... 4th databook states the following: The Power of the White Snake is conferred by the White Snake Sage of Ryūchi Cave, by biting a person and injecting them with its natural energy. Those who survive are deemed worthy of being taught Sage Mode, meaning Orochimaru was bitten, survived and at least received Senjutsu training...