Article one names the Saoshyant as the saviour figure of frashokereti, "born miraculously from the seed of Zarathustra," without setting out how that lineage is actually structured in the fuller Zoroastrian texts. The developed tradition does not describe a single such figure but a sequence of three, spaced across a very long span of time, and the detail matters for how the doctrine compares with later messianic expectation elsewhere.
Pahlavi texts describe Zarathustra's seed as preserved miraculously in a lake, Lake Kansaoya, from which three virgin mothers will in turn conceive three sons at intervals of a thousand years: Ushedar, Ushedarmah, and finally the Saoshyant himself, each renewing the world further and the last completing the renovation article one describes. The structure gives Zoroastrian eschatology a staged, escalating shape rather than a single decisive intervention, three successive deliverers rather than one, each preparing for the next.
Article one notes, cautiously, that Zoroastrian eschatology is "widely thought to have influenced" later Jewish, Christian and Islamic expectation; the three-saviour structure is one of the more specific points where that comparison has been pressed, since ideas of a forerunner preceding a final deliverer appear in some Second Temple Jewish and early Christian material as well. The dating of the Pahlavi sources that spell out the three-Saoshyant scheme in this detail is considerably later than the Gathas themselves, which makes the direction and extent of any influence, as opposed to independent development of a similar staged expectation, a question specialists continue to debate rather than one this comparison can settle on its own.