A psionic Duergar differs from the standard Duergar in the following ways:
Medium Humanoid (Dwarf, Psionic)
Duergar traits, psi-like abilities
A psionic duergar does not possess the spell-like abilities of standard duergars. Instead, it has psi-like abilities.
1/day—expansion, invisibility. These abilities are as the power (or spell) manifested by a psion (or sorcerer) of the duergar’s Hit Dice (minimum 3rd level) and affect only the duergar and whatever he carries.
Duergar characters possess the following racial traits.
Duergar have a sixth sense about stonework, an innate ability that they get plenty of opportunity to practice and hone in their underground homes.