Try
Mononoke, a series putatively about fighting demons but really about human malevolence. The dark storylines are set in some of the most beautiful, and colorful, animation I've ever seen.
Mononoke was preceded by a three-episode arc called Bakeneko that concluded the (licensed) series Ayakashi
Ayashi Samurai Horror Tales. (It's being released on
DVD in R1 in the next few days.) You don't need to see it in order to enjoy Mononoke, but it's definitely worth watching and, in my case, buying.