Completely disappeared without a trace. And deserters, who should have been brought back from previous installments of Heroes.

By the way, the idea about artworks is also good... it's unlikely, but it's possible, and why not introduce it as a gameplay element – you can assign abilities to everyone... And let the type of terrain also affect the random spawning of creatures – like crocodiles near a river, spiders in decaying Necromancer forests, and bears in thickets or snowy locations...

By the way, in principle, you can create purely symbolic animals for each race... for example, for the dwarves, the animal symbol is a bear, for the elves, the animal symbol is a white tiger, and for the Necromancers, a giant spider... here you can calculate the chances of creatures joining (also due to symbolism), for example, white tigers, as proud animals, will be attracted by the harmony of the elves, and spiders – by the smell of decay and dead flesh of the Necromancers...