The Kroot are a fictional species in the Warhammer 40,000 game universe. Warhammer 40,000 is a game produced by Games Workshop.
In the game, they are a species of ferocious carnivores that resemble avian creatures. They are aligned with the Tau Empire, and contribute auxiliaries to the Tau Hunter Cadres. However, they do also work outside of "The Greater Good" as mercenaries frequently.
The Kroot first appeared as a playable race in late 2001; the result of Games Workshop's plan to introduce a new race to the game . However, the first appearance of a Kroot was in the 3rd Edition Warhammer 40,000 rulebook (Priestley, 1998), in a sketch entitled "Other Dangerous Aliens" .
The Kroot are a subset of the Tau playable army, although special rules have been released to field armies entirely composed of Kroot, or as allies to other forces.
The Kroot are a relatively new force in Warhammer 40,000, having been released in October 2001. They were one of the two races chosen by the Development Team to become the new entry into the game, but it was decided that the Kroot would be incorporated into the other new race, the Tau, as a subservient culture.
The Kroot were designed to be brutal, barbaric, and primitive, to provide a contrast between them and the technologically superior Tau. Pete Haines was tasked to develop the character and background of the Kroot, which resulted in the development of the 'learning through consumption' concept that became the core of Kroot society. In the Warhammer 40,000 universe, this means that a Kroot's genetic structure and physical appearance is altered by the genes of other animals and intelligent creatures that they consume, allowing them to swiftly adapt to different environments. This process also allow them to absorb information by consuming an intelligent creature's flesh in a manner similar to a Space Marine with a functioning omophagea.
In February 2002, rules were released through the Chapter Approved section of White Dwarf magazine for the use of Kroot as mercenaries. These could either be included as allies for most other armies; which had been previously hinted at in the background material in Codex: Tau (Chambers, Haines, & McNeill - 2001). Alternatively, the rules could be used to create a force solely of Kroot and their associated forms, although it was noted that the army would perform poorly against several of the Codex armies in a standard battle. These rules were updated for 4th Edition Warhammer 40,000 and made available from the Games Workshop website. However, they are no longer available on the website and haven't been updated for later editions.