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I had an idea, but it's unlikely to be feasible (it slightly violates the rule of "not creating new races"), but I took a closer look at Disciples 3 and noticed that there, with the elves, you can create 3 archers (you can apply different models to the archer models) of different levels with all the upgrades, 1 knight also with all the upgrades (you can apply different models to the knight models), a griffin with one upgrade (corresponding model), and you can slightly adjust the summoned creatures and form them into separate creatures (possibly level 7, because they look powerful; it will require some tweaking, but one can be applied to the warmonger model, another to the lich model, and I haven't figured out what to do with the third one yet).
I wouldn't suggest this idea just like that if I hadn't thought about it for a long time.
There are only 3 heroes there.
Master of Battles (you can use Giovanni's model).
Blind (you can use the archer model and transfer it as a hero model; I saw a mod that changes the textures of the elven heroes, and it had something similar).
Dryad (corresponding model).
You can put them instead of the elves, or you can put them instead of the humans.
All the textures are very high quality, and the graphics in the game are possibly slightly better than in Heroes 5.
I'm just suggesting it; I'm not insisting, because I understand that it's a difficult and time-consuming task.
Added after 23 hours and 43 minutes
The only thing is, I haven't figured out the city yet, but I'm thinking about it