Like her father, she decided to join the tunnelers. She is the lost love of Kalon Kaal. She was imprisoned by Nathuul Kaal because her father, a tunneler, had betrayed him. Kalon and Brethanuae met in Nathuul Kaal’s dungeon.
Brethanuae’s father was forced to endure torment (under the threat that his daughter too would be tormented unless he stayed and accepted his punishment). When she and Kalon escaped from the dungeon, he finally allowed himself to die and escape Nathuul Kaal’s revenge.
Brethanuae and Kalon got married and she was killed while they were on a holiday. There is some mystery about her death – a sudden flash of light and she was killed. Kalon’s memory about the event has been erased. All he can remember is holding her after the event had passed.
There have been some implications that Girsaga was somehow involved in her death because he did not want to risk offspring between her and Kalon due to the Kaal Prophecy.