Story
Verteron Fortress has already been turned into a Balaur den by Krall and Kobold. The Dawn legionnaires will transform into Kobold and look for traces of the High Priestess. For now, gather the illusion magic materials from the Kobold.
After completion (spoilers)
"I assume you intend to use illusion magic to disguise yourself as a Balaur?" Verteron Fortress has already been turned into a Balaur den by Krall and Kobold. The Dawn legionnaires will transform into Kobold and look for traces of the High Priestess. You had to gather illusion magic materials from the Kobold and learn the Krall language for an effective transformation.