This is a "Wild Mass Guess" entry, where we pull out all the sanity stops on theorizing. The regular entry on this topic is elsewhere. Please see this programme note.
The Life And Times Of A Winning Pony
Blossomforth is the time-travelling daughter of Twilight Sparkle and Fluttershy.
From Twilight she's inherited the same manestyle, nerd tendencies, and grumbling snarkiness. From Fluttershy she has the hints of being a Shrinking Violet, the fact that she's a pegasus, and the capacity to be downright mean when riled.