I volunteer DevilHeart77, as intelligent as he is, he will be able to make a few observations before being crushed. Out of curiosity in many works necromancers have some form of soul meld spell. It is very simple and forces two different souls to merge as one, normally resulting in insanity. What would happen if used on two demons, demons are often viewed as insane by mortals, but often with various forms of insanity. I ask because if the river is some form group conscious it will not be doing much as most of those people will think of themselves as powerless and damned.