|Family||Father (UniBank owner)|
|Behind the scenes|
|First appearance||The Departure|
|Last appearance||The Departure|
Karen's father was the owner of UniBank, and Karen was made a Controller so that the Yeerks could get closer to him. However, after Aftran's brother, Estril 731, was killed in a battle with the Animorphs, she followed Cassie home and spied on her as she depmorphed, learning her secret.
Later, Aftran became lost in the woods with Cassie. Cassie tried to convince Aftran to leave Karen's body, at one point giving her own body to Aftran so that Karen might go free. Cassie then made a deal with Aftran: she would morph into a caterpillar and deliberately trap herself in the morph, in exchange for Aftran leaving Karen and never taking another human host. Both Cassie and Aftran honoured their ends of the deal; Cassie was later able to escape from her morph, and met briefly with Karen, who confirmed that Aftran had let her go free.
- Karen's age is never stated; she is described as "young", which presumably means younger than Cassie. Most likely, she is between five and ten years old.
- Aftran asks to Cassie how Marco's "monkey" (as she calls it, it is really his gorilla morph) morph could hurt her. Cassie replies that it's a gorilla morph. Aftran then states that she was taking it from Karen's knowledge, suggesting Karen is around the age of a kindergardener/first-grader. Or that she just doesn't know the difference between gorillas and monkeys.