- Narrator: Jake
The Ellimist introduces the Animorphs to the other player in his game.
Tropes:
- Big Damn Kiss: Jake and Cassie finally kiss in this book after Jake turns out to be Not Quite Dead. This memory leaks into the Howler hive mind, causing them to learn what love is.
- Brown Note: The Howler's signature howl is meant to destroy the brains of those with complex thought. The more complex the brain, the easier it is for the Howler to destroy it. The Animorphs and their non-sapient battle morphs are able to withstand the howls in immense pain, with the exception of Ax, who prefers to fight as an Andalite. Ironically, Marco, whose battle morph has the most complex brain of all the kids, is said to have shrugged off the howl the best.
- Cosmic Chess Game: The Ellimist and Crayak are locked in a competition over all life in the universe. The Ellimist wants life to flourish, but Crayak wants life exterminated, and those he deems worthy of living to worship him. The Animorphs versus the Yeerks are only a small part of this game.
- Curb-Stomp Battle: All six Animorphs versus a single Howler ends with the Howler winning, and it's not even close. This establishes from the off that the Howlers are a threat they're going to have to outthink rather than outfight.
- Eldritch Abomination: Crayak is described as a giant red eye on a throne in the middle of an enormous machine. Jake feels sheer terror when that eye focuses on him.
- God of Evil: Crayak is an entity as powerful as the Ellimist, but with a love of violence and destruction instead of tricks and life.
- Good Thing You Can Heal: Howlers can regenerate from damage in a minute, unlike the Animorphs who need to morph to regenerate their wounds.
- Guest-Star Party Member: Erek shows up as the eighth teammate. Although he can't directly inflict violence on the killers of his creators, his holographic emitter, super-tough body, and general intelligence repeatedly save the Animorphs' lives.
- Heroic BSoD: Ax runs away from the first battle with a Howler because its sonic scream was most lethal to him. He spends the rest of the book sulking over this, even though he knows that it let him survive and none of the Animorphs are mad at him for it.
- Hit Me, Dammit!: A Howler is surprised to see a living Chee in the form of Erek, and tries to get a taunt him while Erek blocks a door. Erek couldn't even if he wanted to, so the Howler loses interest and continues after the Animorphs by blasting around Erek's fingers so he can be displaced.
- Hive Mind: While Howlers are individuals, they have a collective memory they can fall back on for combat experience.
- Human Shield: The Animorphs realize that the Howlers can't harm the Iskoort, and use this to hide behind or among Iskoort to prevent the Howlers from using their most lethal weapons. Erek also repeatedly uses his nigh-indestructible android body this way to protect the kids.
- It Only Works Once: The Howlers are smart as well as dangerous, and don't fall for any trick the Animorphs use a second time. Direct combat? They know they can win. Insect morph escape? They use pesticides. Erek's holograms? They start ignoring them.
- Natural Weapon: On top of their sonic attack, Howlers have claws and teeth that can tear off limbs.
- The Reveal: Jake acquires a Howler and morphs into one with great care. Then he finds that Howlers aren't malicious. Howlers don't know evil. Howlers are grown in a factory and only live for three years. Howlers are children who want to have fun, and see the rest of the universe as playthings to break in a game; they don't realize any of them are people.
- Self-Serving Memory: The Howlers are not invincible, despite what their collective memory shows. It soon becomes apparent that all the Howlers that fail are erased by Crayak so the rest of the Howlers never realize they're not invulnerable or playing games.
- Soft Water: Subverted. Jake lures a Howler over a ledge, where they fall down, and down to the swampy surface of the Iskoot homeworld. The Howler does not survive hitting the water.
- Super-Scream: The Howlers are called Howlers for their sonic scream.
- Symbiotic Possession: The Iskoort are actually the Isk and the Yoort. Yoort are slugs that leave the Isk every three days to feed on Kandrona, much like Yeerks. The Isk are artificial beings created to be bodies for the Yoort, and both halves can't live without the other. If the Yeerks win the war against humans and Andalites, they'll discover the Iskoort and learn that they can live without enslaving other races, which is why Crayak wants the Iskoort wiped out.
- Transferable Memory: The Iskoort can trade memories. The Animorphs buy the memories that the Howlers sold to get an understanding of them, and later upload their own memories into the Howler hive mind to show them that they're sentient beings too.
- Walking Armory: The Howlers bought tons of weapons from the Iskoort after showing up for the first time, and none of them initiate a fight without a dozen flechette guns, ray guns, knives, and so on all strapped to their person. And it's not like they aren't plenty deadly without them...
- Wealthy Ever After: After everything the Animorphs trade him, Guide becomes incredibly wealthy.
- Weird Trade Union: The Iskoort's Hat is their economic society where all beings are divided into castes and guilds to serve a purpose, like the Warmaker Guild for war, the Criminal Guild to give the law enforcement something to do, and the Shopper Guild for the purchase of products.
- Ultimate Life Form: The Howlers are perfectly engineered killing machines. A howl that can destroy complex brains and painfully stagger anything with a sense of hearing, retractable claws and teeth for killing, a spine that can pivot at 180 degrees, powerful regenerative abilities, eyes that can make out vital organs in an enemy, and a Hive Mind that can be easily consulted on how best to kill an opponent.
- You Have Failed Me: The fate of all Howlers who fail Crayak is to be erased from existence. Jake creates a scenario where the Howlers learn that all the things they kill have feelings of their own, causing them to develop empathy. Crayak destroys the Howlers in response.
