In desolate sections of the Abyss, especially the dread region of Thanatos (see Manual of the Planes), strange clouds of fine, white powder hover in the air and crackle with necrotic energy. This strange haze saps the life force of creatures within it, dissipating or corrupting that life force to empower nearby undead.
Effect: Fields of bonepowder haze are lightly obscured. Any living creature within a square containing this terrain regains only one-half normal hit points from healing effects. Furthermore, whenever a living creature receives a healing effect while in bonepowder haze, each undead creature within 3 squares of it gains a +2 power bonus to attack rolls until the end of the undead creature’s next turn.
Usage: Pairing bonepowder haze with undead is a no-brainer. Even without undead, the haze makes any combat more dangerous by degrading healing. Brutes wade into the haze, knowing that the damage of their powerful strikes will persist longer. You can position artillery at the edge of a field of bonepowder haze to obscure the enemy and also hinder ranged counterattacks.
Published in The Plane Below, page(s) 13.