Background Info. History: Orochimaru was originally a student of Hiruzen Sarutobi as part of a three-man team, consisting of himself, Jiraiya and Tsunade. Even at a young age, Orochimaru stood out as a prodigy — his talents, knowledge, and determination were considered by his sensei a sight seen once in a generation.
According to Tsunade, Orochimaru had always been twisted, even back when he was a child. His sadistic attitude was presumably due to the death of his parents, which led him to study kinjutsu and eventually becoming obsessed with learning all ninjutsu. Jiraiya theorized that Orochimaru went down this path in an attempt to forget his painful memories. Sarutobi in particular had very high hopes for Orochimaru, often berating the clumsy Jiraiya and telling him he should be more like his team-mate. After becoming the Third Hokage, Sarutobi hoped that one day Orochimaru would succeed him.