The Flies of Lord Beelzus are the back bone of X23494. They perform a majority of the tasks in building his vast network of tunnels, creating flesh farms, destroying pests, and rearing the Vessels.

Flies spend a majority of their time deep underground, emerging during key seasonal moments to mate and to assist the Royal Guards in the hunts. However, Flies will spawn a number of Flylings which will do work above the surface. The Flylings are not directly related to the Flies created by Lord Beelzus. They are a parasite thought to be painted by Lord Grem with his rotting brush.

Flylings share a psychic connection with their host and will do their bidding. The mental demands of maintaining a connection with a Flyling is very strenuous. Most Flies can only maintain one Flyling at a time; however, the strongest servants of Lord Beelzus have been seen controlling three.

Flies rarely die of old age; however, they often die after slowly succumbing to insanity.