Random theories and speculation · 5:25am Nov 1st, 2014
The Eternal Night may return (Main Series Spoilers)
In Equestria there was a 1000 year period where Celestia, who is associated with daytime, was the sole ruler of the land and was the only one really spoken of existing. During this time, nearing the end of it, she took on apprentices twice. The first was named Sunset, a time near the end of the day. After Sunset left she took on Twilight as an apprentice. Twilight is a time of day later than sunset but before the night proper begins.
A new ruler has recently risen to power at this point. Her name is that of the time of day quite close to the start of the night. EVERYPONY is talking about Princess Twilight now. I would even assert that she's a more common subject of praise than Celestia is now. What if this sequence of names is more than a mere coincidence? What if this sequence of names is a hidden message pointing towards a continuing trend towards the night? What if the return of a land ruled entirely by Luna, Princess of the night is coming and this time it may be unable to be stopped before it fully takes hold.
The only way the Eternal Night was prevented the first time was through the use of the Elements. Following this usage of the Elements they were no longer able to be used by a single being. In fact they required a specific set of SIX beings. Now that the "Age of Twilight" has begun one of those six is Ageless while the other 5 will eventually age and die. With only one of the six remaining the Elements will be essentially naught but paperweights and the way is clear for the rise of the night once more.
Movie Speculations (Equestria Girls Series Spoilers)
Throughout the Equestria Girls (EG) movies it has seemed that Twilight and Spike were "unique" in that there was no counterpart to them in the EG world. Following the ending credits of the newest EG movie there was proof that not only is that not true but EG Twilight has been keeping track of strange occurrences and now has her eyes set on the school that is the main setting of the EG movies. One might think that this would point towards a possible third EG movie. However the only movie that has been announced to be coming "soon" is a FiM movie. Perhaps what this means is that this time around EG Twilight and EG Spike will be coming to FiM Equestria rather than the other way around as in the first two movies.
I've heard naught about the announcement of the "upcoming" movie aside from the fact that they announced a movie and they said it will be set in the standard FiM world. If there is other information then this theory may very well already be proven impossible but it would be an interesting twist. ESPECIALLY if EG Twilight convinced the EG 6 to join her and EG Spike through the portal.