In a multiverse where one can travel through darkness and light, lose oneself and gain oneself back, and have one’s identity copied and recopied, the walls between parallel realities have always been thin. But now, they are also fragile. Where once the occasional blip in one universe could turn a corridor of darkness into a tunnel to another universe, now reality is bleeding into itself on an unprecedented scale. Unwilling tourists don’t even have to leave their bedrooms to find themselves in another universe entirely, transported instantly, whether it’s to the same location in space or off by miles or entire worlds. Just as with the worlds once consumed by the Heartless, some universes have already disappeared.
While the exact root of the problem is unclear, red-eyed and unusually aggressive Heartless and even Nobodies are showing up in those universes that have not already fallen. Time is running out for each of them, and as always there is the danger that Xehanort already knows about all this.
Perhaps he has always known. Perhaps this was the plan, all along.