Margaret Rodheimer is Meg, Weston Rodheimer's deceased wife.

We never meet Meg except through references by Jantzen Hefferly and Weston Rodheimer.

Meg was pregnant when she was killed on a skiing vacation with her husband. Garik Shayk sees a picture of her on the ski slopes in Book 8, Sunchaser's Gambit, when Weston Rodheimer briefly reveals his tortured memory of her death.

Meg is the reason her husband was the first in the program to make the change from human to hybrid. HIs anger at her death drove him to take the chance that he could bring her back to life through the life-altering process of DNA melding with another person. 

We never meet Margaret "Meg" Rodheimer, but she is pivotal to the story. Her death drives Weston Rodheimer's loss of emotional empathy and his careless disregard for the participants in the human-hybrid program whom he considers failures.