Sanctioned routes between warlord territories, the only legal path for invasion under Phase One Combat.
The warlord message announcing Phase One Combat states that combatants may freely enter enemy territory via designated corridors — but no offensive magic may be used during this first ramp-up phase, and no teleport-based spells may be cast.
The corridors are therefore the shape of the war's opening: armies funneling along fixed approaches rather than materializing anywhere they like, which is why Carl's changelings were sent to disarm traps on the The Operatic side and why the Sluggalos describe everyone moving to "one of the two fronts" the moment the shooting starts.
Fixed passages linking warlord territories, sanctioned by the system for legal invasion.
The only lawful invasion routes during the war's opening phase.