Alchemy

There is a point in his greatest movies where Brando ends and his character begins, and i can't think of any other actor who could do that. Look at a Henry Fonda film and its Henry Fonda playing a part. In a Brando film, Brando creates real people. We do not think of Don Corelone as Marlon Brando at all, it's Don Corelone, a man with a long history and a strong powerful presence. The same can be said about Stanley and Terry. That was Brando's unique gift, the only famous actor who was able to totally dissolve into a role, so that the audience forgets its Brando and becomes immersed in the Character.
Compare Brando with somebody like Richard Burton in Cleopatra, at no time do you look up on the screen and think-that's Mark Antony up there, its Just Richard Burton in a Toga and sandals.
Tom Hanks in particular has been playing Tom Hanks for the last 30 years. There is an almost mystical quality to Brando. Pauline Kael called it Alchemy- magical transformation..