Kellin

Kellin is a biologist and physicist by training, but due to a lack of womanpower has been pressed into service as an all-purpose scientist, fix-it, and medico.

With short, single-scene exceptions, Kellin has not been a viewpoint character. She is impatient, frequently suffers from sleep deprivation, and usually has a low opinion of others, save for her sister (and lover) Ress. She has considerable guilt over her invention of the iron oxide bomb, and her incestuous affair with Ress.

The Genetics War
During the Genetics War, Kellin and her sister resided in the relative safety of the White City. At some point, the brilliant scientist was recruited, likely by Petara, to research ways to speed up the terraforming strategy employed by the Daughters to render the planet inhospitable for the Mothers. Kellin's solution, which would come to haunt her, was the iron oxide bomb, a secret she is desperate to keep from her sister.

In the aftermath of the war, Kellin was chosen to be part of the new Earth Colony. Before they left Mars, Kellin was seduced by Ress-- but in such a way to make Kellin think she had done the seducing. Kellin continued to feel guilt about her one night with Ress for a long time.

Earth Colony
Kellin seldom ventured out beyond the ship after the first encounter with the old rex. (Eyes in the Dark)

An exception was a biological expedition, in which she was protected by Quasha, Ress, and Lask. (The Song of Thirteen)

When Jarissy was first (and accidentally) poisoned, Kellin managed to isolate the poison and determine a cure. A sample of this poison was later used by Ress to bring about Jarissy's ultimate demise. (Puppets and Poison)

To Bell The Cat
Ress confessed love for Kellin, and they renew their incestuous relationship. (Leviathan)

It is revealed that both Kellin and Petara know that Ress was involved in Jarissy's death. Petara threatens to let the others know what Ress has done, as well as to let Ress know that Kellin invented the iron oxide bomb, and through these means buys Kellin's loyalty. (Walking Wounded)