So, as you can see, each action effects 6 gods total. The reputation of remaining two gods is not affected.
Not quite. To understand relationships, you need to look at the relationship wheel in the diplomacy screen. Gaining reputation with a god moves your mage closer to that god, which means an equal relationship decrease with the opposing god, lesser gains/losses with the other four, and very slight losses with the remaining two gods. Getting closer to one god will usually get you closer to the gods closest to that one on the wheel, but once you've reached a fairly high level of devotion (represented by the smaller inner circle on the relationship diagram) then getting closer to that god will actually decrease your standing with every other god, including the two who are closest to the god you're following. It's possible to have quite good relations with one god and decent relations with two others; the optimal point for this is represented by the inner circle on the diagram; once you're outside that circle, any improvement in relations with one of those gods will diminish relations with the other two.
Personally, I think I'll try focusing on temples of two adjacent gods, which provide units that complement each other. For example Hellas for archers and either Dauros or Krolm for strong melee.
This sort of approach is possible, and it's one of the strong points of the Humans since they can build temples to any of the gods except Grum-Gog. If you build temples to three adjacent gods you can diversify your temples even further; Helia, Dauros and Agrela are particularly good candidates for this; you get a strong tank, an archer, and a healer unit if you're into combined arms tactics. You also get the first few spells from two gods and most of the spells from Dauros.
Personally, I like starting with Favor of Fervus and building my first temple to Lunord. The spells from Fervus and Lunord are excellent, and Assassins from the temple of Lunord are in my opinion the best temple unit in the game by a wide margin. Beastmasters are a little better than average for temple units, and you get a melee and missile unit combo that way as well. If you start with favor of Lunord and build a temple to Fervus you don't get as many Fervus spells to start with and you trade early Assassins for early Beastmasters, and that's really not a good trade. Getting favor and your first temple with the same god will cost you either an awesome temple unit or a lot of good spells, depending on which god you go with.
For a three god approach, you can pick up favor and build your first temple to the same god. This doesn't work all that well with Lunord or Fervus, since they are bordered by Grum-Gog (who won't give you temple units, you filthy human) and and Krypta (who gives good spells that only work on Undead). Like I mentioned above, I think Duaros is the best god to go with if you plan on chasing three gods. Start with Favor of Duaros and build your first temple to Dauros. From there, don't build any more temples to Duaros; if you alternate temples between Helia and Agrela your status will move to the spot equidistant between the two, with Dauros as the closest even though you only built one temple to him and several to the other gods.
