Does the name Tempest of Set make sense?

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.

Thoth Amon is not the leader of the Toses. He is the leader of the Black Ring. The Black Ring is an order of magicians whose devotion to Set is limited by the magical aid he gives them. The Tempests should technically be loyal to King Ctestiphon, Lord of Luxor, as the monarch of Stygia. Thoth Amon is like the leader of Tea Party of Stygia, having power and relevance only by virtue of of the followers he has gathered to oppose the status quo for self-gain.

1. I Think Kalanthes helps you because you have the power to kill Thoth Amon (he can't kill the Messiahs ;) )

2. I don't know if i am right but i think that the worshipers in Kheshatta are fanatics, they can't decide between friend and enemy ^^

3. Thoth Amon is not your Master. He is the Leader of the black ring. The black ring summons demons or dead gods like the grim grey god. As a ToS you only worship to the religion of Set.

Set is an evil demon god, so yes a bit strange that a priest class has him as favoured god, but not unlikely. Priests classicaly in roleplaying games draw their power from the god they worship. Roleplaying games have had alignments from lawful good towards chaotic evil referring to Dungeons and Dragons. Since you have obviously evil aligned characters like Demonologist (hellooo..?) and Herald of Xotli (Demon god of terror) that make pacts with demons, demonic transformations, demonic pets and Necromancers that summon undead minions and all mages can get "Tome of Erlik". Erlik being a god that was banished to the depths of the earth where he would claim the dead for him self. On the rogue archetype, I would say an Assassin is also an evil character. Mostly poison and unholy damage, fear abilities.

So we got evil mages. Very much! We have an evil soldier, a kind of unholy paladin guy, the Dark Templar, and arguably the Assassin. Having an evil aligned priest class as well shouldn't surprise. :) The question would rise towards any mage class or a Dark Templar that would wash upon the shore of Tortage beach as well. :)