Hive Fleet Chimera had grown exponentially from its latest meals, several more small worlds. 1 even contained a marooned crew of some kind.

The fleet consisted now of 50 Super Massive Hive Ships and a seemingly limitless amount of support craft. Capable of Launching numberless hordes of ground forces. 

The Fleet slowly moved through space towards it's next prey. What the rest of the galaxy referred to as the Triarian Collective. Genestealers had already begun to infiltrate the world and drew the fleet towards it with ever growing speed.

Because they do not utilize FTL travel it will take a long time for the fleet to arrive. But they will not be detected until they are close enough for the shadow in the warp(the effect Tyranids have on FTL and communication technology) to take its deadly hold. 

(The fleet is moving to the recently colonized Collective world, this will be the first contact with a defended world)