Achicahua
The unwoven: Achicahua belongs to the timeline the Rethreading edited out. In the rewoven reality this is River.
The second River at the still pool, and the newer of the two. He split off on the day of the Rethreading in Session 19, so when the party met him in Session 20 he was, as Atezca put it, “just from yesterday.” He had been getting Atezca’s pages the same way River has, and he didn’t believe them until the ravine. In his version the rim came down in the dark and nobody called out.
He is the River who is different in a useful way: he has a hand for cartography and magic. He drew the map that brought the party to the still pool, the arcane drawing that Alina read as two pools joined by a slow teleport, and whose sigils lined up with the ice at the frozen waterfall. He finds his routes by likeness, and he could draw more maps if they find places like this one.
The Name
He had no name of his own until Session 21, when River told Father Joseph everything about the other Rivers and named him Achicahua, strong water. Atezca is the still water that stays where it was left. Achicahua is the current that cuts new channels, and the one who draws the maps between pools.