A few idiosyncrasies in the "Tempest of set" name include
1: Kalanthes is a priest of Ibis, and spent his whole life fighting Priests of Set. Ibis himself was the one who drove Set to the tombs of stygia where he was worshiped only by small cults. Why would Kalanthes help a Tempest of set when he/she washed up on the shores of tortage?
2: Why would the set worshipers in Kheshatta attack a tempest of set when they are one of their own? Furthermore why Would a tempest of set raid the black ring citadel when it's their place of worship?
3: Why would a Tempest of set go against their master; Thoth Amon?
It would have made much more sense to call them "Tempest of Ibis" just to fit in with the lore and backstories of the characters in the game. But I guess it's too late now.
IMO Tempest of Ibis rolls off the tongue nicer.