NCF – Extended list of Neutral creatures.

Overall, it's not very interesting; it's just a monster and another monster.

Added 41 minutes later
For me, the most important thing about a unit is its backstory.

Usually, there are many details, so not everything fits into the description.

A Ghoul is just a monster, a relative of another monster that lives in the Dungeon; it's boring.

Here's an example of a backstory I worked on.
These were goblins with rat skulls. I decided that they were evil spirits that take over corpses and change their form. The resurrection happens without the help of mages, purely due to the evil aura of these spirits – this is the basis for both the rats and the harpies with skulls.

These are general details; then there are individual details, for example, that they hunt in packs, that they are cowardly not just for the sake of it, but for the survival of the species, because only the aura is needed for reproduction.
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The second criterion is the models – without them, nothing will work. For example, the Corpse Eater – without the skull, there was nothing. You can come up with as many stories as you want about it, but without the skull, there's nothing. He almost made me put a stopper on his neck; thanks, Pavlinho.