Sandvich Chefs are a species of clones (that resembled pyros) made by Clone Co, a company that created clones for the general public by forming them with a sandvich that shares the power of Lord GabeN.
They were used to cook sandviches for heavies during battle, to cook sandviches for restaurants, and for personal use. They later stopped working for the masses after the Battle of Clone Co, which made them go rogue. They are currently scattered around the world, with only few still working and tending to their masters, some willing and some that weren't effected by the war.
Months after the battle, mercenaries and surviving Clone Co personnel sought after the clones to convince them to stop being hostile. They only succeeded several times.
It is encouraged by many companies (including Clone Protection Agency) to either try to persuade the clones or subdue them when spotted. Every wild clone currently has a 300$ bounty on them by CPA.