Fire is a terrain obstacle, similar to Plasma, that units can not move through. These tall pillars of flame illuminate a five square radius in Fog of War. The light from the fire, however, only illuminates areas that cannot conceal units and does not show which faction a property belongs to. The fires are on the map during the entirety of the mission and players can neither strategically place any new fires nor extinguish any existing fires. This, of course, does not include Design Room maps, in which fire can be used as a terrain tile.