History Fanfic / Daemorphing

* AdaptationalNiceGuy: The petulant self-centered aspects Canon Tobias sometimes shows when talking to Hork-Bajir are absent in ''Daemorphing'' Tobias, as is Canon Tobias's rejection of the concept that there are innocent Yeerks. In general ''Daemorphing'' Tobias is less reserved, more pro-social, and willing to reach out to people of many species, probably because he's so much less isolated in this series. For that matter, all of the Animorphs and not just Cassie are readier to see Yeerks as people.

* AlienArtsAreAppreciated: Interspecies bonding over art is a recurring theme, whether it be the Paradox Family and Andalite thought-speech-singing, more instances of bonding over stories and legends than can be counted, or Tidwell and Illim's shared appreciation of poetry.

* MercyKill: ''The Abyss'' is kicked off when [[spoiler:Melissa spares a Hork-Bajir-Controller, allowing the Yeerk to infest her and reveal the Animorphs' secrets. The real Hork-Bajir then puts her out of her misery.]]

** The Dust is usually called hrala, rarely Rusakov particles, and even rarer spirit-motes or [[spoiler:the Kolumatiy]], but the only time it's called "dust" is at the end of ''Prometheus in Chains'', where Jake uses it as a description rather than a name.

* HasTwoMommies: Mertil's parents, seen in ''Shattered'', are both women, but he calls them his mother and father - to Poetry's Andalites, "mother" refers to which parent more usually [[BizarreAlienBiology carried the infant in a pouch]] marsupial-style, riffing off of Ax's observation in canon that all ''human'' fathers are male.

* KilledOffForReal: Besides characters who die in the backstory or very early on, such as Elfangor, various characters who either live or die at some later date are killed. [[spoiler: These include David, Edriss, Tom's Yeerk, Alloran, Edriss's "son" Darwin, Arbat, Melissa, and several original characters.]]
* KillTheHostBody: Happens a lot. The Animorphs don’t really have the ability to kill Yeerks any other way, and Aftran reveals that not killing but inflicting severe damage is actually worse - the Yeerk will survive but the host will be killed as useless. Not doing this to Human-controllers gets called out for the specisism it is and is one of the things that leads to them being identified as humans.

* AdaptationRelationshipOverhaul: This series features many characters interacting who either never met in canon, had minimal characterisation, or both. For example, Melissa hates Rachel after she learns who the Animorphs are because she doesn't understand why they have to do such harsh things; and Tom becomes close friends with Ax, Tobias, and the free Hork-Bajir.

* YouAreACreditToYourRace: In ''The Presence of Justice'', [[spoiler:Kalij (formerly Toby) tells Toby (formerly Tobias) that none of the human refugees who lived with the Hork-Bajir for months never bothered to learn the Hork-Bajir language, but Toby points out that Tom did. Kalij says that "Tom is different."]]

* DemotedToExtra: In canon, Tom's second Yeerk was one of the main players in the final battle. Here, he's unceremoniously killed off halfway through, and as a result, the war ends in a completely different way.