Who is Chever? The nation of Chever within Persia was said to be particularly vicious and cruel. Who are they?
Zoroastrian fire worshipers. See the Yaavetz on Gittin either 17a or 18a i forget which.
Artscroll translates them as “Chaldeans”, I believe. However, that doesn’t match up with the history. As far as I could find (I once researched this because I was curious when I learned the Gemara in Shabbos), there was no real major upheaval in Babylonia during the Tannaitic or Amoraic eras. I am no expert, but I would guess that it refers to small pagan Assyrian tribes that probably took over small locales that had most of the Jewish population and these pagan tribes would not have been sympathetic towards Judaism in the slightest.
It seems to be the dynasty of Ardshur who took on Zoroastrianism. The terms referring to them are confusing because it sounds like they came in from somewhere, and that is how Rashi describes it.
HaLeivi: What? You’re saying Rashi got the history wrong? Oh, DY’s not gonna be happy with you.
Aside from that, though, it actually makes sense.
HaLeivi: I mean, the candle/light part makes sense. But I thought that on the whole we got along with Zeroastrians.
I recall reading/learning that they were the Zoroastrians.
Perhaps “coming from” somewhere means the infiltration of the religion.