Changes

By the nature of the hive fleets, fierce resistance on a planet will only make the fleet stronger in the end; for this reason only a few tactics have been found to work. The first is to draw the Tyranids into a large ground battle, forcing the fleet to deploy as large a ground force as possible. Once this is achieved, the planet is evacuated, following with [[Exterminatus]] as the Tyranids strip the life of the planet. This tactic is effective as Hive Fleets are dependent on the impetus gained from absorbing each conquered planet; the Hive Fleet will also have lost the biological "energy" expended to conquer it, including all of the bio-material of the ground forces and by the nature of Exterminatus will not be able to recover any from the planet. This tactic is extreme and also damaging to the Imperium, as it destroys a valuable and habitable planet every time. It has been projected that there may not even be enough habitable planets in the galaxy to stop the Tyranid threat, especially if more Tyranid fleets arrive from outside the galaxy.

1) Insinuating [[Genestealer]]s in the population. This step isn't always necessarily present, but [[Genestealer Cult]]s are frequent enough to warrant mention.<br>

2) [[Mycetic Spores]] are launched from the Hive Ships, and [[Lictor]]s and other Tyranids, such as the Genestealers, begin the attack.<br>