Thoughts on the scenario after completing "Hammers of Fate".

I carefully reviewed the clips featuring Tieru and didn't find any hints of any human, elven, or other settlements. It seems to me that if something like that existed, the developers, with their attention to detail in landscape design, would definitely have included it. And for reconnaissance, you need, at the very least, the scouts themselves. Of course, it's possible that Tieru hired someone (although where would an elf druid, alone on his island, get gold from?) or enchanted someone (which again brings us back to the fact that he uses magic). And then, as soon as the battle with Vaier ends, the illusion of Tieru appears. It's more logical to assume that Agrail's use of the Griffin Heart (by the way, a completely idiotic name – it's unclear what it symbolizes: either a griffin died and its heart was used to create the artifact, or it's a pretentious name for a symbol of the Griffin Empire) caused the ghost of Tieru to appear, which indirectly suggests that he is mentally connected to his artifact(s).
And besides, you yourself stated that Agrail is, to put it mildly, not entirely sane.
I, on the other hand, believe that Agrail is completely sane and wants or intends to use Tieru's help – because, logically speaking, an elf living somewhere incredibly far away, in the Irian Sea, must be powerful enough to send his phantom across vast distances. Therefore, as an ally or at least an advisor, he should, at the very least, be useful.
Now I want to return to one of my messages about the multiplicity of worlds, about which you expressed doubt. Simply, according to the logic of events (or in this case, the scenarios), the first three parts of Heroes take place in another world (I forgot its name), before Jelu and the barbarian crossed their blades. Then Heroes 4 begins with a cutscene about the destruction of this world and the survivors being transported to another world. And in Heroes 5, there is already a completely new concept of the world (precisely the world, not the races). But that's just a side note. I apologize, I don't have time to reply on the internet every day, the connection is not very good. However, we are almost fellow countrymen, right? You have the same problems (I am very envious of Russians in this case).