She rejuvenated herself many times in her long life and she searched for powers which would grant her immortality. She was Kuthuman's lover then.
Kirlen discovered a spell that could give a wizard the powers of a planeswalker, but she did not have enough mana to cast it. Kuthuman convinced her to give him this spell and promised to find enough mana for them both. After destroying the House of Oor-tael, he became a god-like being and forgot about his promise. Feeling betrayed, Kirlen stopped keeping herself young and as a result began to age very quickly.
At the time of the 998th Festival, Kirlen was bent over with age, with hair long since gone from white to a sickly yellow, her wrinkled skin hanging loose on her face as if it had already lost hold upon the bones of her body. Her black robe clung to her slender frame as if she were a skeleton held up only by the staff she leaned against, holding it with both of her gnarled hands.
When the Grand Master of the Arena, Zarel, decided to storm her house to steal her secret spell of planeswalking, she managed to reach her private quarters and cast a spell of teleporting, covering the room in ice and escaping the fall of House Bolk.