I think that Seraph was the previous 'one', and that somehow depending on what decision he made, his mind got left inside the matrix. That could explain why Seraph is the only one that can put up a fight to Neo. If you watch there fight you'll see that neither one of them land a punch or kick, and they seem to be an even match. No one else in the movie, not even Smith could put up that good of a fight, a 100 of them couldn't
also, with the relation between Neo and the oracle, it would make sense that having nothing else to do being trapped in the matrix, that he would guard her
But what about the other "ONEs" There would have been 5, why would only one of them be stuck in the matrix? The Machines aren't that random, they are governed by laws and rules, also how would the ONE get back into the matrix if he was to restart Zion?
__________________ "If you do a bad thing for a good reason, does that bad thing become a good thing? Or is it still a bad thing? And if so, how can it possibly be good to do it?
well if the one restarted the matrix they would still have the equipment to plug into it. I like the Idea of seraph being a residual program left over from the previous one. heck, since the one is so powerful in the matrix then why couldnt he upload his conciousness into it before death? where are the other 4? good question. perhaps they will pop up in the next film. if you watch the trailer there is some creapy dude that looks like a bumb who made a cameo in reloaded. He seems to be a significant character and perhaps he could account for one of the others.
and filled with wrath and despair he mounted upon Rochallor his great horse and rode forth alone, and none might restrain him. He passed over Dor-nu-Fauglith like a wind amid the dust, and all that beheld his onset fled in amaze, thinking that OromŽ himself was come: for a great madness of rage was upon him, so that his eyes shone like the eyes of the Valar.