Run Like Hell

From the introduction:

The infernal gnomes of Niemheim look to expand their influence into the land neighboring their holdings at their hellish masters’ demands. While the gnomes have enacted several plans to claim the Rothenian Plains, they have made few inroads. One gnome cult, the Hellfire Runners, believes the physical power possessed by centaurs is the root of the problem. In the cultists’ minds, the ability to best centaurs physically will ensure free access to the plains. They devised a ritual to create a distorted version of the centaur, fusing gnome and hell hound. The ritual is imperfect and, after a few initial successes, resulted in the deaths of several of the cult’s gnomes.