Theresa Montgomery was sister to shadowrunner Dirk Montgomery.
After her parents death, Theresa did not take the loss well, and turned to simsense abuse to cope.
In 2052, the disappearance of Dirk's sister Theresa led to his investigation into the BTL 2XS, an investigation which culminated in his discovery of the insect spirit hive in Seattle underneath a Yamatetsu research facility. Dirk led a crack team to infiltrate the hive, kill the insect queen and rescue his sister.
Later an insect shaman helps Theresa to be possessed by an insect spirit. As a "good merge" flesh-form, the insect spirit looks exactly like her, has complete access to her memories, and can mimic her perfectly. Although the bug spirit claims that Theresa's self—her personality and ego—remains intact, it is only a lie intended to win Dirk's cooperation. Theresa's personality was destroyed by the insect spirit's possession. For all intents and purposes, Theresa is dead, killed by the spirit that possessed her.
- Augmentation, 13