Cassie hi res.png
Biographical information
Aliases Cass
The Morphing Queen
Cindy Crawford
Resident Ecology Nut
Miss Morality
Mother Earth
The Hypocrite
The Killer with a Conscience
Saint Cassie
Cassie the Animorph
Horsewoman of the Apocalypse
Species Human
Caterpillar (briefly)
Gender Female
Host to Aftran 942 (briefly)
Niss (simulated reality)
Eye color Brown
Hair color Black
Born 1984
Died 1997 (alternate timeline; resurrected)
Family Michelle (mother)
Walter (father)
Unnamed niece
Occupation Student
Assistant at Wildlife Rehabilitation Clinic
Diplomat for the Free Hork-Bajir
Undersecretary for the Interior of Resident Aliens (formerly)
Special Assistant to the President for Resident Aliens
Affiliation Animorphs
Wildlife Rehabilitation Clinic
Chee (formerly)
Yeerk Peace Movement
Free Hork-Bajir
United States Department of the Interior (formerly)
Cabinet of the United States
Behind the scenes
First appearance The Invasion
Last appearance The Beginning
Portrayer Biko (book covers)
Nadia-Leigh Nascimento (TV series)
Masasa Moyo (voice, PC game)
Marilyn Alldredge (voice, PlayStation game)
Sisi Aisha Johnson (voice, audiobooks)
"I'm not trying to be some kind of martyr, or say that I'm always a screwup. I'm not. In my world, making hard choices is part of the deal. Sometimes I'm right, sometimes I'm wrong. Sometimes I just can't tell, even when the mission is over and we've all come out alive, at least."

Cassie is a founding member of the Animorphs, an author and a state diplomat and official. She was instrumental in helping the Animorphs acquire their various animal morphs and played a key role in the Andalite-Yeerk War, being responsible for handing the morphing cube over to the Yeerks. Following the war, she became an author and by the age of nineteen, worked alongside the President of the United States.


Early Life

Cassie's family owns a farm that has been in the family since the Civil War, and has been remodeled into the Wildlife Rehabilitation Clinic; a sort of animal hospital for livestock and wild animals. Cassie helps her dad frequently take care of the wild animals staying there.

Becoming an Animorph

One night, Cassie, along with her best friend Rachel, Rachel’s cousin Jake, his best friend Marco, and a kid Jake saved earlier that week named Tobias decided to take a shortcut home from the mall through a construction site.

There, the five of them find a dying alien named Elfangor-Sirinial-Shamtul and learn all about the Andalite-Yeerk War, including that the Yeerks have already infested a large percentage of humans. To combat the Yeerks, Elfangor gives Cassie and the rest of the teenagers the morphing ability.

Befriending the Enemy

During an attack on a Sharing meeting, right after Jake orders his team to retreat, Cassie tears the throat out of a Hork-Bajir and kills him. Ridden with guilt, Cassie decides she has had enough of fighting and killing and quits the team.

Later, she meets Aftran 942, who is the Yeerk in the body of Karen, a young girl who does not want to be infested. After Cassie and Aftran discuss the ethics of Yeerks taking hosts, Cassie and Aftran make a deal that if Cassie will agree to become a nothlit in a caterpillar's body, then Aftran will agree to leave Karen's body and never infest anyone again. Cassie stays in caterpillar morph for more than two hours and compelled by Cassie’s compassion Aftran keeps her promise and releases Karen.

A few days later, Cassie, as a caterpillar transforms into a butterfly, which resets the morphing clock and allows her to demorph.

Pacifist in a War

Over the course of the series, Cassie struggled with retaining her pacifist nature and violating other creatures’ personal rights. Acting as the moral compass of the group, Cassie was the one who argued against acquiring other humans’ DNA without their permission. On one occasion, she was considering whether or not a buffalo who acquired the morphing technology was sentient or not.


Realizing they are outnumbered, the Animorphs decided to use the Escafil Device to create new Animorphs, with Cassie offering to recruit handicapped children since there would not be a risk of the recruits being Controllers, due to the Yeerks deeming them as defective.

After the Yeerks find out the Animorphs’ intention, a fight ensues and Jake chases Tom’s Yeerk into the forest. As Tom flees with the morphing cube, Jake stalks him in tiger morph, preparing to kill him and retrieve the cube. Cassie, believing that Tom should escape with the cube for reasons she is unsure of, coupled with a desire to save Jake from crossing a personal line by killing his brother, attacked Jake, allowing Tom to flee with the cube.

Having romantic feelings throughout the series, Jake proposed to Cassie before the final battle against the Yeerks, although she suggests that he ask her again a year after the war ends, unsure of whether Jake can live a normal life post-war, should they survive.



"We Animorphs and the newly minted Prince Aximili, with our prisoner, landed Ax's official liaison ship, a sleek Fast-Courier, right in the middle of the Mall in Washington. Not a mall, the Mall, a sort of open green space with the Capitol Building at one end, the Smithsonian Institution and various government buildings on both sides, and the obelisk of the Washington Monument at the far end. We called ahead, not wanting to terrify anyone. There were roughly a thousand cops and twice that many newspeople waiting for us. It was, as Marco said, a "shiver-my-spine moment." A sea of microphones and video cameras and flashbulbs. Ax and Jake, and to a lesser extent Marco and I, gave a sort of brief explanation of what had been happening, and where things stood now. Needless to say, it was kind of a big news day."

To be added


"Cassie was Undersecretary of the Interior for Resident Aliens. It paid less than I spend on corn chips, but hey, Cassie was seventeen, like me, and she was meeting with the President and spending most of her time with the free Hork-Bajir. [...] Anyway, Cassie was a government poo-bah, always racing around here and there in government jets and helicopters, making sure Toby and her people were good and just generally saving the world. Also taking college courses at night because she still wants to be a veterinarian like her mom and dad. That's Cassie for you: Save the rain forest, save some cow with a hernia — the girl just does not get the whole celebrity thing. I mean Wal-Mart practically begged her on hands and knees to take a million dollars to do ads for their jeans, and she said she didn't have time because there was some controversy over an access road into some forest somewhere."

Like the other Animorphs, Cassie became instantly rich and famous from winning the Yeerk War.

At only seventeen years old, Cassie became an important activist, dealing with environmental issues and taking care of the free Hork-Bajir. She was saving the world by day and taking veterinary courses by night so that she would become a veterinarian like her parents.


"I wasn't just Cassie the Animorph anymore. I had been moved out of the Interior Department when the new President was elected. She had appointed me instead to the new position of Special Assistant to the President for Resident Aliens. I was nineteen and I was in the President's sub-cabinet. [...] I was Cassie the Animorph, always would be. I was in history books, after all. But I had a different life to lead now. I was going forward."

After the new President of the United States was elected, Cassie was given a spot in the President’s sub-cabinet and appointed to the new position of Special Assistant to the President for Resident Aliens. With her new boyfriend, Ronnie Chambers, she was scouting new areas for the Hork-Bajir to inhabit when Jake arrived to tell her about Ax being captured. Cassie offers to come but Jake declines, saying that her role is over, and that she is doing what she wanted to do the most.


"An entire human race of Rachels — angry, merciless, aggressive, and equipped with Yeerk and Andalite technology. It was a terrifying specter. But perhaps... perhaps I had been wrong. Perhaps the real menace lay at the other end of the continuum — represented by Cassie. Humans who were softer. Kinder. Well-meaning. And, ironically, infinitely more dangerous."

Cassie is the most compassionate member of the Animorphs, Rachel's best friend, and was Jake's girlfriend. She is very kind and empathetic, often acting as the mediator of the group. Her perceptive and caring nature allows her to sense people's inner feelings and insecurities, leading her to act as team therapist at times. Though she is openly against most violence, Cassie's empathetic ability to read people means that she can be ruthless when she has to be. For instance, she came up with the plan to trap David in morph by playing to his ego.[1] Cassie has the reputation of being a "tree-hugger," due to her love for animals and lack of style. Her nature-loving personality isn't at all shallow though; Cassie has numerous moral struggles and questions about evolution, sentience in animals, the so-called "circle of life," and the morality of the Animorphs' fighting in the war at all. Though Cassie is willing fight when necessary, she desperately seeks a better way to win the war. True to her dream to find another way to win the war than outright destruction of the other side, it was Cassie who allowed the Yeerks to get the Andalite morphing cube, showing the Yeerks that there was another way to see, hear, eat, and experience the other senses they were denied in their natural Yeerk forms than through infestation.[2]

Relationships with the other Animorphs


"Jake and I are closer than just friends. We care a lot about each other. Or at least we used to. Now everything was changing. Everybody was changing. I didn't know who was who anymore. Sometimes, I didn't even know what I felt."
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Jake and Cassie have crushes on each other right from the beginning of the series, and a romance slowly develops between them.  They share their first kiss in The Attack, and in later books they both acknowledge the love they have for each other in their narratives, though they have not stated in outright. Towards the end of the war, their relationship deteriorates and Jake loses trust in Cassie after she allows the Yeerks to gain the power to morph.


"She'd been my best friend forever. Teased me about my clothes as I teased her about her obsessive shopping. How long ago had that been? [...] But the war had touched her. She'd changed, and she'd known she was changing. The war had revealed a hidden part of her soul. She alone, of all of us, she alone liked it. Loved it, even. She had enjoyed the fight. Sometimes I imagined her as a Viking. Or as a knight on a quest. That's what she was: a joyful warrior."
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Cassie and Rachel are best friends, despite being complete opposites. Their friendship becomes strained in later books, as Rachel becomes increasingly drawn to her warrior side and becomes impatient with Cassie's strong ethical convictions.


"Tobias is a nothlit. Someone who stayed in morph beyond the two-hour time limit and got trapped in that morph. None of us are one hundred percent sure it was an accident. Sometimes we think Tobias is happier as a hawk. That he let himself be trapped, on purpose. But none of us has come right out and asked him. At least, I haven't. And none of us has asked if given the same situation he'd do it again. Assuming Tobias chose his fate and wasn't just a victim of a really bad circumstance."
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While they don't interact as often, they are still good friends. He is the closest in attitude to her, and they generally side together on group votes. Cassie's house is physically close to Tobias' territory. In The Beginning it's mentioned that while Tobias has stopped talking to Jake and Marco (after Rachel's death), he still does keep in touch with Cassie.


"I felt a wave of affection for Marco. We had never been the closest of the Animorphs — our connection went through Jake, it wasn't direct. But here we were, in some way the only two real survivors. We had even prospered. Each of us was far better off by most measures than we'd have been without the war."
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Although they are generally on good terms, Cassie and Marco are not close and don't spend much time together. There is some personality conflict between them, as Cassie's morality is diametrically opposed to Marco's ruthlessness. However, at the end Cassie notes that she and Marco are really the only "true survivors" of the war and together they agree to try and break Jake of his depression.


"I didn't want to say the words. I didn't want to. But Ax was more than a friend. How many times had he risked his life to save mine? I couldn't count the number of times I'd been down and only his flashing tail had brought me out alive."

Cassie and Ax don't interact often, although she does comfort Ax after Estrid leaves him. When Ax becomes sick with yamphut, Cassie shows concern for him before she performs life-saving surgery on him.[3] Ax feels hatred for her after she allows Tom to take the Escafil Device and thus granting the Yeerks the power to morph, citing that Cassie is the most dangerous Animorph since she is most like Seerow. However, they end up back on terms later on.


Book Morphs

Morph Book Acquired
Horse The Invasion
Osprey The Visitor
Wolf The Encounter
Squirrel (Magilla) The Message
Bottlenose Dolphin (Monica)
Black Garden Ant The Predator
Cockroach The Capture
Great Horned Owl
Humpback Whale The Andalite's Gift
White Rat (Courtney) The Secret
Wolf Spider The Android
Brown Bat
Spider Monkey (unusable; Sario Rip morph) The Forgotten
Jaguar (unusable; Sario Rip morph)
Human (Rachel) The Reaction
Racehorse (Minneapolis Max) The Unknown
Parrot (crimson) The Escape
Hammerhead Shark
Mole The Underground
Mosquito The Decision
Tyrannosaurus Rex (unusable; Sario Rip morph) In the Time of Dinosaurs
Caterpillar (most likely unusable) The Departure
Butterfly (most likely unusable)
African Elephant The Solution
Giant Anteater The Suspicion
Baby Ringed Seal The Extreme
Polar Bear (Nanook)
Giant Squid The Exposed
Chimpanzee The Experiment
Eel The Sickness
Yeerk (Illim)
Hork-Bajir (Jara Hamee) The Prophecy
Cockatiel The Proposal
Orca (Swoosh) The Mutation
Southern African Cheetah The Weakness
Pit Viper The Arrival
African Cape Buffalo (Buffa-Human) The Hidden
Honeybee The Other
Hork-Bajir-Controller The Unexpected
North American Beaver The Resistance
Dragonfly The Answer

Television Show Morphs

Morph Episode Acquired
Horse My Name is Jake, Part 2
Rabbit The Message
Cockroach The Escape
Crocodile The Reaction
Mouse (off-screen) The Leader, Part 2
White-headed Capuchin Changes, Part 1

Cassie is shown to have a total of 9 morphs. However, in various episodes she mentions "acquiring a bunch of animals" and "acquiring as many animals as I could" implying she has many more.

Books Narrated By Cassie


  • She is more talented at morphing than the others. Ax notes that Cassie could easily become a professional estreen, one who morphs as a form of art, due to her inherent skills.
  • She has the unconscious ability to unravel any alternate/parallel universe/timeline.[4]
  • All of the models for the Animorphs featured on the front and inside cover had been changed since the series began, mostly because the original kids had grown up and moved away to college (since book 41). Only Cassie's model (Biko) remained close enough to still model for Animorphs. And of course Ax, who is actually just a cardboard cutout.
  • In keeping with her non-violent nature, Cassie is the only Animorph who lacks a unique battle morph; she typically assumes a wolf form when required to fight, which most of the team acquired while investigating Yeerk activity in the mountains.
  • In 1999 three different Animorphs toys of Cassie were made.
    • Her transformer toy turned into a wolf.
    • Taco Bell released a Cassie transforming toy that became an anteater.
    • She was one of three Animorphs who combined all together in the Tri-Rex transformer toy to become a comparatively large Tyrannosaurus Rex.
  • Cassie is the only original Animorph not to accompany the group on the mission to rescue Ax at the end of the series, and possibly the sole surviving original Animorph after the series' end.
  • In the TV series, it's Cassie who's allergic to crocodile DNA, not Rachel. Also, unlike Rachel whom would transform into random animal several times when the allergic symptoms shows up, Cassie only suffer partial transformation on random parts of her body instead.



TV Series


Animorphs Jake | Rachel | Tobias | Cassie | Marco | Ax | David
Auxiliary Animorphs James | Collette | Timmy | Kelly | Craig | Erica | Julio | Liam | Tricia | Jessie | Judy | Ray