The xenos emerged from the intergalactic space of the Local Group of galaxies, their Hive Mind drawn to the Milky Way by the psychic beacon of the Astronomican transmitted by the Emperor's presence in the Warp from Terra.The first officially recorded contact with the Tyranids for the Imperium of Man came during a Tyranid attack on an Ocean World called Tyran, and from there Hive Fleet Behemoth continued directly towards the center of the galaxy, consuming all the worlds in its path.We have given the horror a name to salve our fears; we call it the Tyranid race, but if it is aware of us at all it must know us only as Prey." The Tyranids are an extragalactic composite species of hideous xenos that is actually a space-faring ecosystem comprised of innumerable different bioforms which are all variations on the same genetic theme.The Tyranid race is ultimately dedicated solely to its own survival, propagation and evolutionary advancement.
At that time they were not an important race in the Warhammer 40,000 universe.In later editions they became a playable faction in their own right, and it was revealed that the Genestealers (first popularized in Space Hulk) were in fact part of the advance reconnaissance element of the main Tyranid Hive Fleets.The first recorded contact between the Imperium and the Tyranids places their appearance in the Eastern Fringes of the galaxy in 745. However, it is rumoured that the Ordo Xenos of the Inquisition had identified possible appearances of this xenos species as far back as the 35th Millennium.Tyranid Hive Fleets travel through space by using gigantic, organisms genetically engineered to travel through a vacuum known as Hive Ships, which move in groups which can be likened to very large locust swarms.
Typically, Tyranid Hive Fleets move in ad hoc formations known as Tendrils, migrating to nearby inhabited planets after consuming all the biological and organic material on a recently invaded planet and breeding, often reproducing many times their original number.The Tyranids travel in great fleets of gigantic living creatures that serve as spacecraft, each of which is home to countless lesser Tyranid organisms grown in the bubbling organ-sacs of the vessel’s reproductive chambers.