over the course of the "reloaded" and "revolutions" plot arcs, he has three brief altercations with warriors of zion. the first is with ballard, which he stages in order to get to know him; the second, with neo, to prove he is the one. the third takes place in the closing stages of "enter the matrix", after the conclusion of "reloaded" but before the beginning of "revolutions". seraph summons either niobe or her first mate ghost to meet the oracle. whoever he summons, he first tests that person with another battle, in order to "test his/her heart's resolve" (or, more technically, a challenge-response authentication). this heavily implies that seraph acts as a firewall for the oracle, only allowing those he deems worthy to proceed and make contact with her.