Deathmare

A deathmare looks like an ordinary, medium-sized riding horse with a perfect jet-black coat. On the frontier coast that coat is a clue, since the red mineral dust of the region tints every other animal's hide reddish, but the creature appears only at dusk or after dark, when few notice. It waits quietly beside a road or in a field for someone to approach or climb on, and sometimes ambles into a camp as though hoping for a handout. Nothing in its calm manner hints that it is undead.

Whoever mounts a deathmare, saddled or bareback, cannot get off again; only remove curse lets the rider leap free. The horse cannot be steered either. It gallops toward the closest hazard to kill its passenger, leaping from a cliff, plunging into deep water or even charging into a camp and lashing out so that the people there are forced to cut down its rider.

If someone sees through the disguise before mounting, the deathmare attacks with hooves and teeth. Only silver or magical weapons harm it, and even facing those it refuses to flee from its intended victim.

Deathmares turn up in any land and climate, usually not far from some deadly feature they can use, though a hungry one may wander further afield. They gather no treasure, but they tend to reuse the same killing ground several times before moving on, so searching nearby cliffs, rivers and chasms may turn up several bodies with their belongings.

Each deathmare is the spirit of a horse tortured and killed by a cruel, evil master. It returns to take revenge on every rider, good or evil alike, and feeds on the life force of those it kills. It keeps hunting until its former owner dies, then quietly fades away.