From PathfinderWiki
Halflight, second from left.

The apocalypse horse Halflight is the mount of the Trelmarixian, the Apocalypse Rider of Famine. The advanced nightmare's glossy ebon skin stretches tight over its bones and its form resembles a horse in prolonged starvation. Its eyes glow with the eerie radiance of Abaddon's eclipsed sky. Trelmarixian does not ride his steed so much as inhabits it, the nightmare vomiting the Apocalypse Rider out from its mouth, nose, and eyes once they arrive at their destination.1