A Hive Tyrant (Tyranicus praefactor) is the massive Tyranid bioform that serves as the main battlefield commander of a Tyranid swarm, a synapse creature that stands above the rank and file Tyranids.
Hive Tyrants serve as the commanders of all the Tyranid forces deployed on a given battlefield, for they share a special synaptic link to the Hive Mind. This link makes a Hive Tyrant one of the most important of the Tyranid synapse creatures.
From photographs taken at GamesDay and at Warhammer World.