Species information

Sector 5, RG-21578-4




Brightly colored feathers

Number of Limbs


Special Attributes

Sentient; Avian;
Biological Engineers

Behind the scenes
First appearance

The Hork-Bajir Chronicles

Last appearance

The Prophecy

The Arn are an extinct avian race, original inhabitants of the Sector 5, RG-21578-4, and the biological engineers of the Hork-Bajirs.



The Arn were an avian race that originally inhabitants of the Hork-Bajir homeworld. They have four legs, short wings, and two enlongated arms ending in claws. They are covered in brightly colored feathers vary wildly in shades. Their faces are dominated by glittering eyes and small, red mouths.[1][2]


The Arn were masters of biological innovation, so much so that they had little ability or interest in traveling past their own moons.[3]

After an asteroid collided with their world and destroyed much of the life of their planet, the Arn created an entirely new ecosystem to keep the planet alive. The Arn then decided to shield themselves from any more such catastrophes by moving their settlements into the deep chasms caused by the disaster.[4]

They created the Hork-Bajir in order to care for and support the vast jungles of high-rise trees. The Arn also created the creatures of The Deep to ensure no intrepid Hork-Bajir enters the Arn settlements deep in the planet's chasms, which was known to the Hork-Bajir as Father Deep. The Arn controlled these murderous creatures with chips implanted in their heads, which allowed them to give the creatures simple commands.[5]

Andalite-Yeerk WarEdit

When the Yeerks invaded the Arn/Hork-Bajir homeworld, the Arn denied the Yeerks any possibility of being made into Controllers, or any Yeerk acquisition of the Arn's advanced technology. They achieved this by altering their body by making an already weak blood vein even weaker, so that when a Yeerk enters the brain, the vein will pop, thus killing the would-be host and Controller. Upon realising this, the Yeerks used the Arn for slave-labour and target practice and eventually exterminated them through mass murder, exhaustion, and starvation.[6]

However, one Arn who played a major role in the battle for the Hork-Bajir, Quafijinivon, traveled to Earth on a stolen Yeerk light freight ship and studied and absorbed every human language. He found the Hork-Bajir colony and the Animorphs. There, Quafijinivon used a technique known as ixcila, whereby a dead individual's 'soul' or 'essence' would find a host and become alive again. In this case, that person was the Hork-Bajir Nothlit Aldrea, Prince Seerow's daughter. Quafijinivon solicited the Hork-Bajir and the Animorph's help, and they traveled to the Hork-Bajir world to help the dying Arn create Hork-Bajir in his lab.[7]

Cassie had to share her mind with Aldrea's memory so they could find a stash of weapons that Aldrea had hid on the Hork-Bajir homeworld. This also allowed them to read each other's thoughts and memories. Cassie learns all about Aldrea and her lover, a Hork-Bajir Seer named Dak Hamee, who died when the Yeerks enslaved the Hork-Bajiir.[8]

Known ArnEdit




  1. The Prophecy
  2. The Hork-Bajir Chronicles
  3. The Hork-Bajir Chronicles
  4. The Hork-Bajir Chronicles
  5. The Hork-Bajir Chronicles
  6. The Hork-Bajir Chronicles
  7. The Prophecy
  8. The Prophecy
  9. The Hork-Bajir Chronicles

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