A hive fleet is a large armada of living, biomechanical starships created by the Tyranids for the purpose of gathering the raw materials and biomass necessary for the reproduction, evolution and expansion of their species. A hive fleet is used to attack and strip star systems of their biomass using the full range of Tyranid bioforms. Only three primary Tyranid hive fleets and a host of smaller splinter fleets have ever come into direct contact with the Imperium of Man, but they have all brought devastating damage and loss of life.