I have a theory about Starlight Glimmer: after her appearance in The Cutie Re-Mark - Part 1 and The Cutie Re-Mark - Part 2 I am beginning to think that she might be a blood or distant relative of Star Swirl the Bearded.

She has shown that she has strong magical abilities that surpassed Twilight Sparkle, it makes me wonder if Starlight is truly related to Star Swirl.