As a child, she developed a dark birthmark that grew and exuded an aura of evil. The elves with whom she was left to be raised performed an exorcism on the child, intending to remove the evil and capture it. Instead it escaped and traveled through Faerun absorbing life energy and taking the form of a drow named Kilil.
Many years later, Kilil joined with an army of creatures from the outer planes who sought to release their army on Faerun using her and Cybriana. However when Kilil and Cybriana touched, they merged into one being, who took the name Kyriana. During this adventure, she also befriended Selune, the goddess of the moon, who was living in Waterdeep.
A short time later, Kyriani was again called on to aid in closing an extraplanar gate. During the battle, she was again separated into Cybriana and Kilil by magic. This was possible because she had never fully accepted her evil half, and therefore was not whole. Once Cybriana could accept that she, like her father, had both good and evil inside, she was able to merge with Kilil for the second and final time.
Either shortly before or after these events, she apparently became allied with the first Blackstaff. On a number of occasions she would provide him with information (such as the presence of Selune in Waterdeep, or actively spy on noted figures (including having an affair with the crimelord and masked Lord of Waterdeep, Carrill). In return, Khelben Arunsun would use his magic to aid her in escaping from the city watch and secretly protect her from both enemies and the authorities.
Kyriani was also notorious for the number of lovers she maintained, of many different races.
After the Time of Troubles when Selune left Waterdeep, Kyriani was given ownership of a bar in the city and became a high ranking member of Selune's faith.
When Khelben Arunsun died, Kyriani continued as a friend and advisor to the second Blackstaff, Tsarra. In 1399 DR, the Year of Fallen Friends, Tsarra was killed in battle against a group of vampire-wizards. Kyriani retrieved Tsarra's blackstaff, and returned it to Blackstaff Tower for safekeeping. Upon her arrival, she was named as the third Blackstaff.
After Kyriani's death, her spirit remained in Blackstaff Tower to guide and advise future Blackstaffs.