Is that an icon from the internet, and you created a model based on it? That's great.
As you can see from the names of the skeletons, there are certain regions – the Black Forest and the Rotting Mire. In the Black Forest, the undead build their kingdom with castles, forges, research centers, and other things, while in the Rotting Mire, the undead simply run around and do pointless things, like the Chaos creatures in the Chaos Wastes.
Initially, the plan was for the hero model in armor to be associated with the Black Forest, and the swamp undead would simply be skeletons in cloaks. After replacing the hands and feet with paid gloves and boots, I can also replace them with skeletal ones.
But then I realized that I needed black and green models for both knights and mages, and in general, it's better to create unique models right away, and I kind of got discouraged(((