The Furnace is a collective of approximately 40 combat engineers and technical specialists who hire out for demolition, fortification, and technical warfare operations. In a city where most mercenary groups sell fighters, the Furnace sells the ability to reshape the physical environment: blow open a wall, fortify a position, rig a building for demolition, build a defensive emplacement, disable infrastructure, or construct improvised devices for specific tactical purposes.

The collective emerged from the construction and demolition industry — former blast technicians, structural engineers, electricians, and mechanics who discovered that their skills were worth more in the security market than in legitimate construction. Furnace operators work alongside other mercenary groups, providing the technical support that pure combat operators can't: breaching charges placed precisely, communications equipment installed under fire, defensive positions built from available materials, and the occasional improvised weapon that turns the tide of a fight.

The Furnace is small and specialized, but their reputation for technical excellence makes them a force multiplier that larger organizations pay premium rates to access. A team with Furnace support is qualitatively different from a team without it — they can go through walls instead of around them, can hold positions that should be indefensible, and can deploy technical solutions to problems that bullets alone can't solve.