"Heroes 5". But are they really "Heroes"?

At least because they belong to different factions. Therefore, these are completely different creatures (if Warlocks have specially bred servants, then in the Swamp, it is the strongest unit, absolutely equal in power). The difference is significant. They are simply different breeds. But I don't understand why the griffins of Erathia are so similar to the griffins of Ashan. Yes, there is not enough diversity in the universe if different worlds are so similar.