What would cause the Roaring?
In Chapter 1, Ralsei says that "a terrible calamity would occur" if the balance between light and dark was shattered, obviously referencing the roaring. So, is the world at risk if there are 2 dark fountains? No, because at the end of ch3, we discover that there was a dark world in the shelter. So, in ch1, there were already 3 simultaneous fountains: castle town, card kingdom, and the shelter. BUT in Chapter 4, we discover that there were 2 dark worlds in the church, bringing us to 4 active dark worlds at the same time: castle town, the shelter, atrum, and the 3rd sanctuary. So we must ask, what is the real thing that triggers the roaring? Is it really the number of Dark Fountains, or is it something else? (also, we could have kept the flower shop Dark World without causing the Roaring because the total would be lower than ch4)