In Forge Of Fury, a party of Dwarven adventurers entered Idalla's chambers to clear out Khundrukar. Her story to split the party made little sense, but she was able to charm Wurgym Caurakril and take most of his energy with a life-stealing kiss before hiding in the Material Realm, where the adventurers were unable to follow. They eventually left, and she remained waiting in Arundil's study for her next rare meal.
A Succubus native to the Lower Realms, Idalla appeared as a stunningly beautiful woman of statuesque build and perfect figure. Her lust and desire to consume was typical of her species; she behaved as many other succubus did, completely consumed with the desire to corrupt souls. Otherwise, she remained empty and unfeeling.
Idalla was brought by Arundil Dhaldohr to the Material Realm through powerful, if evil, conjuration magic. Arundil summoned her to his den in Khundrukar, in a futile attempt to protect his home; he believed he could bind Idalla to his service, and install her as a permanent protector of the Foundry. However, he misjudged her own fiendish abilities, and she quickly overpowered his will. She toyed with him cruelly until finally draining his life force, resulting in him becoming a Ghost that haunted Khundrukar's halls.
As part of the terms of Arundil's magic, Idalla could not leave his study den, resulting in her becoming extremely bored over the century that she remained in the den. Nonetheless, she remained sharp whenever a rare interloper appeared in the stone halls, playing the role of a captive of a powerful Wizard who lived on a lower floor. She would use this to split any parties that entered, before preying on those who remained behind to guard her.