Yeah Orochimaru knows too much.. he is also the strongest Sannin as Hiruzen has recognized him as. Oro can instantly absorb Chakra even Senjutsu. Kabuto can't beat him. Sasuke even admitted that the only reason he could beat Oro was because he was weakened and coming from Sasuke that says a lot.. especially since Suigetsu said the same thing. Orochimaru even got praise from Hashirama and Tobirama.