Lilith is a Zombie Drone that transformed thanks to some experiments that the company made [before the earth explote] with her. Because they realised some strange changes in the worker drones and what was the thing that was responsable of the mutations. After the studies they made to her, she was considered as a dangerous thing that shouldn't get public for the reputation of the company. But atleast they knew that the mutation should happen to every worker drone like a virus.