Found: sci-fi/fantasy (spoilers) alien planet with genetically recreated horses

I'm tracking down a book trilogy where the humans are the aliens, they came from earth and when they arrived on this planet they find that all their nightmares come to life at night (witching hour type stuff), magic is a thing and so are what seem to be facsimiles of gods. One male lead is something like a priest/witch-hunter, and the other is a vampire type guy who's killed his wife and maybe his son. He lives in a forest that may or may not be haunted. There is a race of feline people, with one joining the two male leads, and one of the males does some magic that changes her appearance to look more human. Towards the end of the trilogy, it's discovered that the planet itself is sentient, and the monsters and gods have been it's way of trying to communicate with humans.

I remember one of the covers had a white-haired man dressed in black standing on a white tree, with a black and purple color-scheme.

Probably the Coldfire trilogy by C. S. Friedman, starting with Black Sun Rising. I don't remember feline people but there may have been some.

>2 antqueen: thank you!