A Black Slayer resembles a tall, spindly humanoid with an elongated, horned head, exceptionally long arms and hand ending in sharp black talons. They first manifest as a flat, silent shadow moving along the wall or floor; in this form, they are immune to all spells and weapon attacks. When in wall-shadow form, a faint cool breeze can be felt emanating from them. They can leave a wall in 1d4 rounds at which point they become fully corporeal and affected by all normal and magical attacks. When corporeal, the Black Slayer is matte black over its entire surface, except for its eyes which shine like obsidian. As a corporeal Black Slayer moves, it makes a faint scratching, crunching sound as of charcoal blocks or soft stones being rubbed together. They have no voices, and make no other sounds.

 Such beings are created through arcane rituals and are maintained by the life force of the summoning priest or wizard. The death of a Black Slayer, by spell or weapon, inflicts damage upon the controller equal to thrice the damage of the killing blow.

 Black Slayers have the ability to slowly pass through wood and stone walls, and often attack victims in their beds by appearing from the walls closest to them.
 
Combat: In combat, Black Slayers slash with their formidable talons. Once every other round, a Black Slayer can fire 1d2 Magic Missiles at their opponents in addition to its clawing attacks; the missiles emerge from pits between the creature's eyes where the bridge of a nose should be.

 They can move through walls at a rate of 1 foot per round, and any time they are moving through solid material, they are unaffected by spells or weapons. Black Slayers can blend almost perfectly with natural shadows and become 90% invisible, reducing their AC to -3 with respect to creatures unable to see by infravision or Elvensight. In the presence of bright light (such as a Light or Continual Light, but not torches or lanterns) their AC increases to 4.

 Black Slayers receive only ½ damage from non-magical slashing and piercing weapons. They take full damage from non-magical bludgeoning weapons and all other magical weapons.

Habitat/Society: Black Slayers are magical constructs, built from the life energy of the wizard or priest controlling it. As such, they have no society and can be sent to any habitat across the world.

Ecology: Black Slayers are not part of the natural world, and have no true place in it. They do not eat. When killed, Black Slayers solidify into a form which resembles a statue made from soft charcoal. They are easily crushed and scattered. If the head is crushed, a large black gemstone will be found embedded in the center of the skull; it is worth 250gp, but radiates strong evil. A Black Slayer can also carry a scroll case within its body to be found upon the creature's death if its victim escapes it. Such messages are often sent by weak Black Slayers, in order to cause considerable grief but still be killed, to inspire fear of the Ebon Blade among high ranking officials.