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"I'm free, Cassie. She kept her promise. I'm free."
―Karen to Cassie[src]

Karen is a young human girl who was the former host of Aftran 942.


"She had wanted out of the Hork-Bajir body. She wanted out of the war. What could be a safer, more peaceful host than a little, human girl? The assignment was to watch her father. He was the billionaire owner of UniBank. Being close to him gave Aftran access to all sorts of information and vast amounts of useful cash. The Yeerks wanted to make the father a Controller, but hadn't been able to yet. So Karen had been taken, and made into a Controller to watch the true target: her father."

Karen's father was the billionaire 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.[1]


  • Karen's age is never stated, although she is described as being very young. Aftran confuses Marco's gorilla morph for that of a monkey, and then says that Curious George is the closest thing Karen knew of. Additionally, Cassie remarks on whether Karen even knew about caterpillars becoming butterflies, since Aftran would have known had Karen known, further implying that Karen is very young.