These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Cassie. Is she The Empath who genuinely does not like to emotionally hurt people and persuades others to not hurt others as well, but did what she had to in a war where the stakes were humanity and Earth? Or is she a sadistic, hypocritical and manipulative bitch that will leap at the chance to put someone to the psychological thumbscrews if the opportunity arises? Or is she simply a bit of a moron struggling through the war?
Tobias: Emo with wings, or The Lancer who, as he spends the first books unable to morph, is the only one able to objectively see the risks and benefits of each morph?
Rachel, valiant and skilled fighter or unhinged psychopath (not so much alternate, as her slow drift into Blood Knight and PTSD is canon).
Marco, The Lancer, tactical and strategic genius, or just a fucking asshole who's only good for coming up with horrifyingly ruthless plans and complaining?
Jake, skilled leader, or just some insecure jock who made everything up as he went along and led five child solders to their inevitable War-is-Hell mental breakdown?
David, a lost and confused boy who's had his life completely destroyed and doesn't know if he can trust his "saviors", or a ruthless sociopath who has no qualms about murder and doesn't give a damn about the human race as long as he's safe?
And Taylor: Cold hearted torture technician or mentally damaged Broken Bird who can only express her bizarre love for Tobias by Breaking the Bird.
BLAM Episode: Cassie has an entire book that's one, The Hidden. A random buffalo somehow acquires morphing powers as the Yeerks cause trouble with Helmacron technology. It's as bad as it sounds.
Megamorphs 2: In The Time of The Dinosaurs: A nuclear sub explodes, tearing a hole in space-time that sends all the Animorphs to the time of the dinosaurs. They meet the Nesk and the Mercora species, getting caught in the war between the two. For reasons never explained, morphing won't heal Tobias's broken arm in this adventure. The K-T extinction comet arrives and kills all the dinos and aliens, as well as rocketing the Animorphs back to their own time. After this adventure, the Animorphs find they can not morph into their acquired dinosaur forms.
Broken Base: Some fans liked the secret-guerilla-war aspect of the series, and thought the final story arc ruined the series. Others, conversely, see the final arc as ten shades of epic, and see it as the best-written and greatest part of the series.
Similarly, some fans liked the, uh, open-ended conclusion, as it brought the series full circle. Some thought it was just an easy (and lazy) way for Applegate to get out of writing a real ending.
Visser Three's very first appearance in the very first book culminates in him going One-Winged Angel and eating Elfangor. Not just killing him, EATING HIM. And then following it up with a terribleBond One-Liner.
The Drode. Though not as menacing as his master and borderlining comedic at times, he shares Crayak's homicidal bloodlust and happily serves his agenda of genocide.
And let's not forget Crayak himself. In a series full of shades of grey, he's about as close to pure evil as you're going to see. In The Ellimist Chronicles we learn his goal is the genocide of almost every living thing.
Evil Is Sexy: Subverted. Taylor is described as very attractive, but is so artificial and emotionally screwed up that no one cares. Pointed out by Tobias when he morphs Taylor and recieves far more positive male attention than the real thing:
"We were mirror images, literal carbon copies. But I was alive. Taylor wasn't. Not really. I had a sense of humour. Taylor had a coldness that enclosed her like a shield. The kid could see this. Anybody could."
Fanon Discontinuity: A lot of fans simply gloss over some of the more awful ghostwritten books.
The ending of the series.
Fridge Horror: David's fate - rats only have a lifespan of two to three years. So instead of a death sentence, the Animorphs just gave him a slightly prolonged death sentence.
Girls Need Role Models: Subverted. Initially, Rachel is the obvious choice as the feminist role model in the series (strong-willed, good-looking, personable, bold, courageous, capable in combat, etc etc), with Cassie acting as her meek best friend. However, by the end of the series, Rachel is miles away from a Mary Sue, her "bold and courageous" personality ultimately evolving into that of a sadistic action junkie. Cassie, on the other hand, while proven to be smart and capable, remains a relatively passive character uninterested in leadership qualities, stemming from her belief nonviolence. This makes her an atypical feminist character in that while she can take a more active role she simply chooses not to.
In the alternate future Jake visits in #41, the only part of the New York skyline still recognizable is the World Trade Center.
In book #37, Rachel deliberately crashes an airplane into a skyscraper.
Also, in book #46, there is discussion of how America is complacent because they have no real enemies. And then Ax threatens to fly a plane over the middle of a town and detonate a nuclear device.
In book #54, which was published in May 2001 but set in 2002 or thereabouts, Jake mentions that since the existence of aliens was revealed to the general public there's been a rise in terrorism, particularly religiously motivated terrorism.
In Megamorphs #2, the Animorphs help rescue a nuclear submarine that has gone down. After they finish, Ax asks what the submarine is for, since he figures it’s too large to be an exploration vessel. Jake explains that it’s part of the navy, which leads to this conversation:
<What enemy?>
<Well . . . okay, we don’t exactly have one right now,> [Jake] said, feeling fairly idiotic. <But we used to. And we may get one again.>
<We’re shopping all the sales,> Marco said brightly. <Enemies “R” Us, Enemy Mart, J.C. Enemy. Don’t worry, we’ll find one.>
It Gets Better: The beginning of each book is loaded with the same exposition about the Yeerks and "I can't tell you my last name" and "We can't stay in a morph for more than 2 hours" and "You see, every three days they have to..." and so on.
David - lost his entire life through no fault of his own, was kidnapped by kids he didn't know and forcibly recruited into a war he wanted no part of and faced the threat of death from both sides of the conflict. His final fate just hammers the nail in.
Taylor - lost her arm, leg, and face in a fire. Became a human-Controller in exchange for getting them back. Got infested by a psychotic Yeerk, who's fusion with her own unbalanced mind drove them both over the edge. She'd be pitiable if she weren't so damn evil.
Magnificent Bastard: Visser Three and Visser One approach this in their respective backstories, before the Villain Decay (and in Visser Three's case, insanity) set in. David and Tom both fancy themselves to be this, but are usually seen as just Smug Snakes. The one who probably comes the closest to this trope is, of all people Jake who really cracks out the gambits before diving into What the Hell, Hero? territory.
Marco's Moral Event Horizon came when he planned to perfection, and executed an operation that would have culminated in the death of his own mother, who was then host to Visser One. The episode showcased Marco's logic and ruthlessness taken to its extreme conclusion and showed how far he was willing to go to achieve a strategic goal.
Jake flushes seventeen thousand Yeerks into space during the final battle. What makes it a Moral Event Horizon is his inner monologue beforehand, in which he totally dehumanizes Yeerks, describing them as "parasites" and "subhuman" and claiming that they brought their deaths on themselves. Made worse by the fact that, unlike every other possible attack on helpless yeerks, it was completely pointless — these weren't temporarily helpless enemies who would soon be in a hork-bajir host trying to kill them. This was the final battle; those yeerks' lives had no impact on the animorphs' future survival.
Tobias has a hideous one in Megamorphs #02 which is so badly written that fandom prefers to treat it as Fanon Discontinuity.
Rachel really goes over the edge in the last few books. That scene where she tries to run over Captain Olston comes to mind.
David crossed the line into from troubled kid to villain when he dumped Jake's fatally injured cousin Saddler down an elevator shaft and took his place in the hospital, justifying it by claiming "that kid was toast."
Esplin 9466, of course, crosses it in the first book when he murders Elfangor by eating him.
Edriss 562, in Visser: "I made Jenny breathe."
In The Hork-Bajir Chronicles, Aldrea uses a Yeerk ship to blow the shit out of a makeshift Yeerk Pool, with no time given to the morality of her actions. Of course, her family's murder just pushed her past the Despair Event Horizon, so it's a little hard to blame her.
Paranoia Fuel: Thanks to their fantastic capacity for imitating their hosts, Yeerks can be anywhere, even inside the people you know intimately. Yes, you could be talking to an alien parasite who's putting on an elaborate act and doesn't mean a word he/she says while your genuine best friend/close sibling/beloved parent/ significant other is watching you be fooled, and is mentally sobbing because no one realizes they're a prisoner inside their own head, and you'd have no way of knowing. At all. The yeerks make a few rare mistakes, due to having their own agendas and personalities, but aside from a couple isolated incidents the yeerks are absolutely undectectable. Combined with the books' Literary Agent Hypothesis setup, this makes for some very creepy Mind Screw.
Also because ot the Literary Agent Hypothesis, you realize that the insect you just killed could have been one of the Animorphs.
Even though the Chee are good guys, the concept of people around you being Nigh Invulnerable extraterrestrial robots using holograms to make themselves look human is rather unsettling.
Villain Ball: David had to start carrying one before the Animorphs were able to outwit him.
Villain Decay: Visser Three. He's completely immoral and monstrous, but as a consequence of appearing in almost every book and not killing the Animorphs, he quickly starts to come across as a blundering clod. Visser One even acknowledges this in the Visser Chronicles, comparing him less-than-favorably to the Helmacrons.
Tobias. He starts the series out as a skinny, blond-haired loser Jake saves from bullies... and Jake is the closest thing he has to a friend, despite the fact Jake thinks he's weird. His parents are dead, his only two relatives fight over which one of them HAS to have him. He then gets trapped as a hawk by the end of the first book. He then goes on to have an epic identity crisis, start a semi-Interspecies Romance with a girl who really wants him to drop the "interspecies" bit, realize that the alien who died saving them is his father, get captured and tortured, realize that his mother isn't dead — she's amnesiac and crippled, and watch Jake send the love of his life to certain death. About the only good things that happen to him are Rachel, his girlfriend, and Ax, his best friend and uncle. They both die. For a series as dark as this one, Tobias stands out for his Woobieness.
The worst part is that he honestly feels his new situation is an improvement. To clarify: Stuck fighting an alien invasion involving thousands of conspirators with only four human kids while trapped in the body of a hawk and fighting the instincts of the hawk to retain his own humanity is a step UP for him.
Really, just about every character falls into some category on the Woobie spectrum. Even David, the sixth Animorph who turns on the others has his moments. About the only one who can't be considered Woobie-ish to some extent or another is Visser Three himself.
The Yeerks are the misunderstood variety for the most part. They are basically blind, sentient slugs who only take hosts to compensate for their biology. Only those in power and those seeking power can be said to be really evil, as most of them are either swept up in the propaganda or afraid to challenge superiors.
