However, the "underground Styx's River" that where Blackwater converged in the Southernmost Region was very unusual. According to Iron Axe's report, along the way from Choke Swamp to Endless Cape, Styx's River became less thick and the stagnant fog turned thin. Several Styx' s Rivers intersected at Blackwater Valley where men could even hear the roar of the water splattering onto the rocks beneath them when they were standing at a higher spot.
Roland speculated that the composition of the Styx's River water changed as it flowed. For example, the stagnant fog Iron Axe had described in his report might be a kind of toxic gas emitted by Blackwater, or a product of the reaction between some subterranean materials. That might explain the reason why during centuries of evolution, the natural lightning or man-made fire did not set the Blackwater Valley ablaze, and why no one could survive in Choke Swamp.
