Lightning Dust is a Equestrian Pegasus that once tried to become a Wonderbolt alongside Rainbow Dash at Wonderbolt Academy, first appearing officially within Season 7.
Personality
Lightning Dust is, in essence, very similar to Rainbow Dash. She is very willing to win, and very competitive to others when involved in any activity. She is also rather cocky, and not afraid to talk down her opponents.
However, she is noted to be far more reckless in her approach to things, to the point of endangering others in order to have a thrill, or cheat altogether in order to win. Rainbow Dash stated that it was these traits that made her unable to qualify in Wonderbolt Academy.
History
Prior to the My Little Universe story, Lightning Dust was with Rainbow Dash within the Wonderbolt Academy, as a very reckless individual. However, as Rainbow Dash remained, she was kicked out due to her behavior.
Season 7
She makes her return for the Inter-Species Race, very willing to win the contest. Prior to the race, she ran into Rainbow Dash, making it clear that the race has already been won since she will be involved in said race, teasing Rainbow Dash about her slacking in becoming a Wonderbolt. Just before the race started, she saw Garble mocking Rainbow Dash, and she made it clear that he should keep quiet, as it was ponies who out-duked Torch so many years ago.
When the race began, Lightning Dust kept very good pace with Rainbow Dash and Goldstone. Wanting to win though, she acted more and more reckless during the race, even breaking the rules to make that happen, stating that it didn't matter and all that would matter is her beating Rainbow Dash. This included knocking out the racers, and even hurting others to keep ahead. This got to the point when Rainbow Dash knocked her out of the sky, disqualifying both herself and Lightning Dust in the process.