A thin Veil
The veil between sanity and madness ripples from time to time. The border between the two is never distinct, to begin with. The veil dances with time and disturbances, weaving back and forth over the lands and the walker of the path betwixt.
Take a breath, watch the veil flicker. Let it out again and see what moves away with signs of life. Every breath is painful, every moment a battle. The veil flares wide, and then swirls in closer than your skin.
Through the veil, and out again. Step by arduous step. Slowly, the end crawls nigh.
The veil remains.