Need help with a name for characters in my book?

I am writing a fantasy novel and having difficulty coming up with a name for this group of evil creatures. They ride horses and are hooded so nobody really knows what they are. The people believe them to be headless spirits from the underworld, which is basically what they are. But I don't want to call them the black riders or the dark riders because that's already taken haha... They need a really intimidating name but not something cheesy like the hooded brigade