After reading the new dark timeline lorebook something about the ending looked familiar. [spoiler]At the final battle the darkness and the light combined in large quantities. The last time this happened was during the collapse when the Yang Liewei got sucked into a kugelblitz and Mara Sov formed the Distributary. I believe Elisabeth, overcome with grief and wishing she did things differently, unwittingly made her wish come true after getting sucked into a new kugelblitz. Just like Mara Sov she created a new universe where time moves much faster and bends to the will of the first who entered. It is in this universe that all of destiny so far has taken place, all the while Eris and her army of dark guardians are right outside slowed down to nothing. If this is the case than our guardians will inevitably put a stop to it. Once Elisabeth has perfected the new timeline the city will stand strong and be able to send reinforcements to the outside universe. Eris will think she's won and then litterally out of nowhere an endless stream of uncorrupted guardians will spring into attack. This is potentially the plot of lightfall.[/spoiler]