The Swarmlord is a uniquely powerful Tyranid biomorph. Amongst the billions of creatures created by the Tyranid Hive Mind, there exists one as old as the Tyranid race itself, the ultimate conduit through which the Hive Mind's implacable will is enforced. This creature is to a Hive Tyrant what a Hive Tyrant is to a Termagant. It is a monster of darkest nightmare that has preyed on empires and overseen the extinction of entire civilisations. It is a legendary destroyer of world and its names are legion. It is the Tyrantlord of the Hive Mind, the Herald of the Great Devourer and the Destroyer of the Kha'la Empire. To the Imperium of Man, the latest interstellar civilization to face this ancient predator, it is the Swarmlord, and it represents the greatest Tyranid threat to the galaxy. The Swarmlord is the pinnacle of the evolution of the Hive Tyrant bioform, a truly unique monster. The Swarmlord is essentially immortal, like a Hive Tyrant, as once killed it is reborn by the Hive Mind with the exact same experiences, character and knowledge, in essence becoming stronger than its predecessor every time because of its new experience. But unlike a Hive Tyrant, the reincarnation of the Swarmlord appears to be a stress induced response that is triggered only when conventional strategies of the Hive Mind fail and greater resourcefulness and tactics are needed. To this end, the Swarmlord possess more autonomy from the Hive Mind than any other Tyranid creature, and its connection with the Hive Mind is so strong it can emerge amongst any Hive Fleet, transcending any physical limitations separating the different Fleets. The Swarmlord has aeons of battle experience and bloodshed to draw upon. As weapons the Swarmlord wields four bone sabres, crackling with disruptive power, that are capable of slicing through adamantium and force fields as if they were nothing. They differ from commonly seen Tyranid Boneswords in that each sabre has a crystalline growth, not indigenous to the galaxy, at its core that partially protrudes through the blade's serrated surface. The Swarmlord can parry with these sabres at such speed that its foes find it all but impossible to inflict a hit on the creature.
- 745.M41 - Tyran and Thandros - The Swarmlord lead the final assaults against Tyran and Thandros during the Imperium's first contact with the Tyranids.
- 745.M41 - Battle of Macragge, Battle of Cold Steel Ridge - The Swarmlord directed Hive Fleet Behemoth to defeat every one of Marneus Calgar's and the Ultramarines' tactics. Calgar himself was almost killed by the Swarmlord, but managed to escape alive with the help of his Honour Guard while the Swarmlord killed the Commander of the Guard Aloyseus.
- 745.M41 - Battle of Macragge, Battle of the Polar Fortresses - The Swarmlord lead the attack on the Polar Fortresses of Macragge defended by Captain Invictus of the Ultramarines' 1st Company. In the end, the entire 1st Company was killed and official Imperial reports listed the Swarmlord as slain.
- 997.M41 - Holdur Sector - The Swarmlord returned to attack the Imperium, leading the swiftest and greatest planetary invasions of Hive Fleet Leviathan. In the space of four months the Swarmlord oversaw the absorption of two dozen worlds including Talon, Chapter planet of the Storm Falcons Space Marines, and Endragiga, a major shipyard of the region. Latest Imperial reports indicate the Swarmlord is assaulting the Orks of Octarius.
- Date Unknown - Scouring of the Megyre System
- Date Unknown - Destruction of the Bryynar race
- Date Unknown - Consumption of the Ork WAAAGH! Gorgluk
- Codex: Tyranids (6th Edition) (Digital Edition), pg. 59
- Codex: Tyranids (5th Edition)