what is smiths true role? savior,controler,gurdian,demon?

who does smith represent?
i know everyone elses real world connections and religion connections but who is smith? please someone tell me ,i can only think that he is based on something that every one has inside them a mix of control or suppressed rage?

Smith is Neo's exact opposite, his archnemesis. He is the balance of the equation, and he changes as Neo does. He could also be taken to represent all evil, since everyone has some 'bad' in them & smith 'brings it out'. Is that how the world will end?