Fans of the Animorphs

As a Yeerk.... well, it's intrinsic, to some degree. Yeerks quite simply don't often get the sort of normal life experiences that most other sentient species have. They don't get taken care of by parents, they don't get to experience the world, they don't get to fall in love or be parents themselves. They don't often get genuine friendships, or hobbies, or physical pleasures, or form fulfilling and genuine relationships with people, much less grieve if those bonds are broken somehow. They acquire knowledge of all of these things secondhand--they get the what, but not the how or why, no underlying framework of understanding for the deeper elements of emotions and life; she can predict reactions, and manipulate them admirably, but she has difficulty truly understanding them in all their complexity and nuance. Needless to say, it's enough of a taste of the forbidden fruit to be enticing, but not quite enough of substance by itself to amount to much. Also, they could be considered to never truly get a "pure" experience of the world--they can't. They're parasitic slugs that absolutely require another host to interact with the world, one that's reasonably intelligent. Their every experience is filtered through what a host thinks and feels about it, what it does and says, how it reacts, how it struggles and resists and protests, what its physical body is like.... everything is tinted and distorted, however minorly, dualized and at a remove. Even as Edriss wonders at the insanity of the split-brain design in humans, Yeerks "naturally" are forced to have such a design too, with Yeerk brain and host brain operating in a similar vein. Having what's technically three minds in one body, with a Human Controller, is just upping the complexity exponentially.

That feeds into how actively Edriss screwed herself over by selecting the hosts she did, as well. Edriss is used to that situation. It can't be anything but that. Which is why she ended up so disappointed with her first two hosts; the defeated soldier and Jenny Lines were nothing. They were wastelands, worthless and ignorant, broken and defeated shells that barely had any purpose to exist, much less any use to her or society at large. She needs that duality, and she needs it to be a dynamic one. She prefers hosts that can challenge her, that she can find useful, that can make her learn and grow. In that sense, she likes a personality type surprisingly similar to herself--again, the intelligence and resourcefulness that Eva and Allison Kim display are rather similar to each other, and to her own behavior in some respects. She craves not only a useful pawn, but in some sense, a peer.

Because she likes having someone who could be considered a worthy adversary, that's exactly what she got. Eva and Allison Kim were intelligent, cunning, sophisticated people, who longed for freedom and who wanted to do everything they could to counteract their imprisonment. Allison Kim established a camaraderie early on, by actually talking to Edriss rather than just screaming and raging, learning from her and passing on learning herself, keeping her mind agile and her hope alive instead of giving in to despair and futility. She played games with Edriss to try and exploit intentional lapses in control--and also resisted seizing them immediately just for the sake of controlling herself, rather biding her time for opportunities that were advantageous, like when she nearly killed them both in a traffic accident. She was willing to sacrifice her own life in pursuit of freedom. She was willing to resort to trickery and manipulation of her own--as when she used their flow of information to maneuver Edriss into believing that she needed to not only research and learn about humans and their cultures to be able to conquer them, but that she needed to experience that cultural immersion to be able to truly understand them.