This perfect crystal sphere emits a faint white glow.

A fiendslayer crystal helps you fight creatures infused with evil.
A weapon with this crystal attached deals an extra 1d6 points of damage to evil outsiders, the weapon is treated as good-aligned for the purpose of overcoming damage reduction and if the weapon scores a critical hit against an evil outsider, that creature can’t use any teleportation abilities or spells for 1 round.
Any evil creature grasping a weapon that bears a fiendslayer crystal gains one negative level, which remains as long as it holds the weapon and disappears when the weapon is no longer wielded. This negative level never results in actual level loss, but it cannot be overcome in any way (including restoration spells) while the weapon is wielded.

Prerequisites: Craft Magic Arms and Armor, align weapon, good alignment.
Cost to Create: 2,500 gp, 200 XP, 5 days.