These areas of sharp, rugged stone are formed when demons are trampled by other demons or otherwise violently absorbed into the surrounding surface. Most commonly encountered in the Abyss, demon jags could occur anywhere a demonic horde swarms.
Effect: Squares containing demon jags are difficult terrain, but any creature can move through the space normally by taking 5 damage per tier for each square entered. Demons are immune to this effect—the spars yield to their passing or retract into the ground. Furthermore, a demon occupying a square of demon jags can use its variable resistance without reducing its limit for the current encounter.
Usage: Demon jags serve well as walls and ramparts in demon lairs. Those unusual demons that have any degree of patience use the jags to slow or wear down approaching enemies.
Published in The Plane Below, page(s) 13.