For those of you who have been following me a while, this takes place before "Rarity's Little Problem" (for those trying to setup some chronology).
For those who aren't familiar with my work and don't get the joke, take a long look at Pre-Bleachy Belle ([link]
) and a long look at Dinky.
Now then, let the speculation begin! Before anyone asks, this is about as explicit as I'm going to get with revealing who Sweetie's father is. Because, I don't know.
UPDATE: No, this isn't part of a series. There's going to be no direct sequel to this one (sorry). Also, the idea of Dinky and Sweetie being half sisters seems so ... believable the more I look at it. I mean not only the Pre-bleachy Belle color I randomly selected, but look at how they both have two-toned manes and tails!
That's a hint. Look for the Unicorn Colt with a two-tone mane and a darker complexion.