The Hauler is a human-based monster which is based on a version of the
Soldat Eins, in which an unwilling subject has been combined with the
Cadou parasite and machinery. Unlike the Soldat, Haulers were not designed for combat and as such their bodies were completely unmodified - as their name suggests, they were created to act as helpers and not much else. However, they learned to use makeshift weaponry to defend themselves, as a
Cadou controlled the host and it had an innate need to protect itself.
The
Cadou was supplemented with machinery and electronics to help facilitate the movement of the host. The human brain was for all intents and purposes dead by this point, therefore a headpiece was installed which allowed electrical connections to continue. The headpiece resembles a visor / headset and has a red LED or laser attached to the front, presumably to aid with some kind of electronically aided vision.
If the headpiece is damaged, they become far more aggressive and unpredictable as their controls have been disturbed. It also is revealed that their eyes are fully functional behind the visor. However, they are still very weak and can be defeated relatively easily despite this.