Animorphs

Animorphs (CIC: KVZ-7958-737-KA) is a children's series ostensibly written by K.A. Applegate (but mostly ghostwritten) during the late `90s and early `00s that focuses on a group of young teenagers fighting a secret war against aliens, called Yeerks, who are trying to take over the Earth.

To put a twist on the theme, in the first book, the main characters are given the ability to turn into any animal for two hours at a time, provided that they've absorbed or "acquired" said animal's DNA. The aliens taking over are basically brain slugs who often use Hork-Bajir (think walking blender) or Taxxons (giant cannibalistic centipedes) as their mind-controlled hosts.

Characters
There are six central protagonists, the Animorphs, and several main antagonists in this series.

Jake
Jake is the leader of the Animorphs. He has a strong, decisive personality and is fiercely loyal. His preferred battle morphs are a Siberian tiger and a rhino, his favored flight morph is a peregrine falcon&mdash;the rhino is simply brute strength when he needs it, but the tiger and the peregrine are fast, strong, and precise. He is the person who links all the other Animorphs together by acquaintance at the start of the series; he is Marco's best friend, Rachel's cousin, Cassie's love-interest (though they are both too shy to do anything more than moon over each other) and Tobias's friend (he protected him from bullies on at least one occasion).

Rachel
Rachel is both a fashion-conscious, feminist gymnast (though she protests that she is too tall to ever excel at the sport) and a headstrong, battle-hungry warrior type. Her favored battle morphs are a grizzly bear and an elephant, her favored flight morph is a bald eagle; all large, heavy, brash morphs capable of doing a great deal of damage with no subtlety or precision at all. She is Cassie's best friend and Jake's cousin, and later becomes Tobias's love interest (which is... complicated).

Marco
Marco is a smart-ass. He uses humor to defuse tense situations, or in any other situation, but he is also a shrewd planner and strategist. His favored battle morph is a mountain gorilla (which has the useful ability to use its hands in a human sort of manner, i.e. open doors without breaking them), and his favored flight morph is an osprey. He came up with the term "Animorphs" to describe the group.

Cassie
Cassie is their closest thing to an animal expert&mdash;her parents are vets and run the Wildlife Rehabilitation Center, which is one of the places that the Animorphs usually pick up new morphs. She's a conscientious environmentalist as well, and once argued that the Animorphs could use their powers to help ecologists and other scientists to find out more about animals. She is Rachel's best friend and has a crush on Jake. Her favored battle morph is a timber wolf and her flight morph is an osprey, like Marco's. She is an estreen, or naturally talented morpher.

Tobias
Tobias is the child of a broken home, whose life pre-Animorphs consisted of being shuttled back and forth between an uncaring aunt and an equally uncaring uncle. He was bullied at school, and Jake stepped in to help him. In the first book he deliberately becomes trapped in the body of a red-tailed hawk, becoming a nothlit, and although he regains his morphing power in the course of the series, he keeps this as his body. He has a nebulous romantic interest in Rachel, made difficult by their being different species, and is perhaps closest to Ax. It later turns out that he is the son of Ax's older brother Elfangor (in human morph), making Ax his uncle.

Aximili-Esgarrouth-Isthil
Ax is an Andalite cadet, or aristh, found by the Animorphs in a crashed Dome ship in the ocean. He does not have a preferred battle morph, as few things are as effective in a fight as his own body (and this also means that he does not have a two-hour time limit on his fighting), but he occasionally fights as a cheetah or a rattlesnake. He has a human morph (a blend of the four human Animorphs; this technique is known as a Frolis Maneuver) which he uses when he has to go out into the human world, and his flight morph is a Northern harrier.

Chapman
Hedrick Chapman is a human-Controller and, in the early books, the vice-principal of the school that the Animorphs attend. He voluntarily became a Controller to protect his daughter, Melissa. Nevertheless, controlled by the Yeerk Iniss-Two-Two-Six, he is a major source of trouble for the fledgling Animorphs.

Visser Three
The only Andalite-Controller and the main Big Bad, he seems to have a new and exotic alien morph for every confrontation. He is ruthless and violent, wanting to ascend up the ranks and become Visser One. Taking over the Andalite War-Prince Alloran-Semitur-Corass was quite a coup for him. His given name is Esplin-Nine-Four-Double-Six Primary.

Visser One
A human-Controller&mdash;the first human-Controller, in fact. She led the initial Yeerk survey seeking for infestable species on Earth, and returned to take over the invasion when Visser Three's efforts proved less effective than expected. Her given name is Edriss-Five-Six-Two.

Aliens
The Animorphs universe is rich with diverse alien species, but the most important ones are the Yeerks, Andalites, Hork-Bajir, and Taxxons.

Yeerks
Yeerks are gray, slug-like, about two or three inches long, and basically blind and deaf in their natural state, though they have a rough sort of echolocation and can sense other things by means of small "palps." They communicate by means of sonic squeaks. They feed on Kandrona rays from their sun and nutrients in the Yeerk Pools they live in, and get about by swimming, hopefully straight into the ear of an unsuspecting host. It takes three Yeerk parents to make baby Yeerks&mdash;they merge themselves together and then break apart into hundreds of tiny "grubs," destroying the parents in the process. The offspring are named with a given name and a number, indicating which grub they are: for instance, Edriss-Five-Six-Two is the five hundred sixty-second grub to emerge from the Edriss tri-parent. In the rare case of two Yeerks growing from one grub, a double-numeral and an ordinal are appended, as in Esplin-Nine-Four-Double-Six Primary or Secondary/Lesser, respectively. (Yeerk names may also be written shorthand: Edriss 562, Esplin 9466.) Yeerks don't appear to have genders&mdash;presumably any three Yeerks can reproduce together&mdash;but they take pronouns according to the gender of their host, or whatever suits them best.

On their homeworld, their natural hosts are the Gedds, a slow-witted, slow-moving race with barely adequate senses. The Yeerks themselves, on the other hand, are very intelligent and very organized. They first got a taste for conquest when an Andalite exploration mission landed on their planet. The leader of the mission, Prince Seerow, took pity on the Yeerks and showed them Andalite technology, for which the Yeerks thanked him kindly and then betrayed their teachers, turning their new knowledge of space travel and other worlds to their own purposes and Seerow's everlasting shame. Given the chance to escape their planet, the temptation of new, different, superior hosts proved too much to resist, and so off they went into the galaxy, infiltrating the Taxxon world, the Hork-Bajir world, and eventually Earth (among about fifteen others). The rest, as they say, is history.

The Yeerk Empire is governed by the Council of Thirteen, one of whom is the shadowy Yeerk Emperor. Under the Council are forty-seven Vissers and a number of Sub-Vissers. Yeerks-infested beings are known as Controllers: a Yeerk with a Gedd host is a Gedd-Controller; if he takes a Hork-Bajir host, he is a Hork-Bajir-Controller, etc.

Andalites
The Andalites are a race of centaur-like beings, but with several key differences. For one, their fur is blue or purple. Their lower bodies are more like those of deer than horses, and their backs slope down to long, sinuous tails that end in deadly scythe-blades. They have delicate hands with seven fingers, and while their faces are basically humanoid, they have no mouth, slit nostrils, and two extra stalk-eyes in addition to their main eyes. The stalk-eyes are rooted at the top of the head and can roam freely in all directions. They eat by crushing grasses under their hooves and absorbing the nutrients. They communicate via telepathy, or "thought-speak." Males are larger, with bigger tail-blades, while the smaller females have lesser scalpel-shaped tail-blades and purplish fur.

Andalite culture is fairly rigid, with defined expectations of each and every member of society and rituals for just about everything. They evolved from nomadic herd creatures, eventually coming to form large urban settlements, then abandoning that uncomfortably cramped lifestyle for smaller, agrarian family units, each to its own dwelling, known as a "scoop", with a fair bit of open space between scoops. Their families are similar to those of humans, with two parents and one or two offspring (if any). Andalite names are tripartite, as in Elfangor-Sirinial-Shamtul, with a given name followed by a second name passed down from a parent (Sirinial is Elfangor's father's second name, also), and a third of unknown significance.

While Andalites are basically good, priding themselves on personal honor and respect, as a species they have an unfortunate superiority complex and tend to look down on other races, whether because they're less intelligent, less advanced, less morally upright, etc. etc. The better ones do it with compassion, while others are contemptuous or even downright racist. Their rigidness also extends to strict gender roles, with males encouraged to join the military and females expected to pursue civilian vocations, specializing in arts and "pure" sciences. While it is clear that part of this is to do with the inescapable physical differences between males and females&mdash;a larger male tail-blade is simply better for combat than a smaller female one&mdash;and females aren't necessarily valued less, this differentiation doesn't do them any favors in the eyes of humans. They also have a regrettable attitude toward their disabled, labeling them vecols and shunning them from society, supposedly so that they may find the only dignity available to them in solitude.

The Andalite military is governed by a body known as the Electorate, under which are Princes (a title of rank, not royalty). Variants include War-Prince and Captain-Prince. Every Andalite warrior must, by definition, have a Prince to serve under. The lowest rank is cadet, or aristh.

After the event of Seerow's Kindness (which also refers to the law they since put in place against sharing their technology with other species), the Andalites went to war against the Yeerks to stop them from spreading across the entire universe. Unfortunately for Earth, the Andalite forces were too few and too far away to help, though they did make an early token effort due to the influence of Elfangor. After his Dome ship was destroyed, though, they just didn't have anyone to spare.

Morphing technology is an Andalite invention. The ability is given by means of contact with the Escafil device, which looks like a shiny blue cube.

Hork-Bajir
Hork-Bajir are generally of low intelligence, except for the periodic genetic "flaw" known as a Seer, which is of above-average human level intelligence. Notably, they are absolutely covered in spikes, which makes them very desirable hosts for the Yeerks, but normally the blades are used exclusively for harvesting the tree bark that makes up their diet. Left to themselves, Hork-Bajir are herbivorous and quite peaceful. Males are known to sport three head-spikes, while females have two.

Taxxons
Taxxons are giant sentient centipede-type aliens with an insatiable hunger. They will eat anything, even themselves, if given a chance. They volunteered to host Yeerks in exchange for being fed lots of interesting things from multiple different planets.

In Fanfiction
A lot of fanfiction for the Animorphs these days tends to be from older teenagers or young adults who still remember the series fondly, but occasionally there are fics from younger fans who have discovered the series only recently.

"Extra Animorph" stories are not at all uncommon, despite the fact that they actually had one of those in canon and it ended up with the guy being trapped in a rat morph for the rest of its natural life because it didn't work out. "If it ain't broke, don't fix it" seems to be a foreign concept to many Sues.

Agents Native to this Continuum

 * Ilraen-Aroline-Fothergill
 * Iskillion-Galuit-Elendil
 * Orken 7861
 * Jara Hamee (canon)
 * Zan Holbar

Missions in this Continuum

 * "Eyes of a panther" (crossover with The Lord of the Rings), Agents Jaster and Threnody (DMS, LotR)
 * "GEM STONED: Yeerk Buster," Agents Tawaki and Tangara (DMS)