The Hauler is an irregular mutant created by Karl Heisenberg using the Cadou parasite and Mold.
As with all the 4 Lords, Heisenberg was given unrestricted access to the Cadou to assist Mother Miranda in locating a suitable vessel to bring back her daughter. Heisenberg took the opportunity to try and create viable bio-logical weapons that he planned to use to overthrow Miranda.
Heisenberg was very interested in mechanical enhancements and the Hauler was the first prototype version of the creature that would become the viable Soldat B.O.W using corpses as a base. Male corpses were implanted with the Cadou in place of its heart and then blasted with electrical stimuli. This, combined with the regenerative powers of the Cadou saw this new creature reborn as a walking corpse. Haulers were considered brain dead by Heisenberg, but were intelligent enough to yield weapons such as axes.
They were though comparatively weaker than most other Cadou experiments and were mainly used as guards to the factory. Some specimens were buried in graves and would attack on impulse.
Despite the glaring failures of the Hauler, the prototype served its purpose and enabled Heisenberg to create the Soldat series of B.O.W