Mastery of Twisted Shadow
( Player's Guide to Eberron, p. 126)[General]
You gain the ability to reach into the Plane of Shadow when casting an illusion, concealing yourself in the raw shadowstuff drawn forth.
Prerequisite
Knowledge (the planes) 2 ranks, Spellcraft 4 ranks,
Benefit
Whenever you cast an illusion spell, you can choose as a free action to grant yourself concealment for 1 round per level of the spell. Multiple uses of this feat don't stack; only the longest duration applies.