Unified ideologies of factions in Heroes 1-5.

That is one of the questions. Take my favorite Necromancer as an example.
In the second part—they are supporters of Archibald and do not yet possess powerful influence. Their ideology is to secure a place in the sun by stepping out of the shadows.
In the third—Necromancers are one of the strongest and most independent Factions. They have gained their own great heroes (Sandro, Lord Haart). And here, a struggle for power begins both within the Necromancer ranks and for dominance over Antagarich. Their ideology is to conquer the world!
In the fourth—Necromancers are so beaten down that they are forced to ally with the Kreegans. There is no longer any talk of struggling for power over the world, only a desire to survive. And their ideology is to unite with whoever helps them "survive".
In the fifth—Necromancers are descendants of mages, as in the second part. They are seeking immortality once again. But at the same time, they are a very strong and independent faction. And here, the ideology is revenge!