Rainbow Dash Concept Art

Rainbow Dash, also know as "The Rank 1 Pegasus" by Line Ark, is both a ranged and melee fighter armed with long twin "hook blades" and occasionally a clockwork autogun.  She has survived her miserably lost battle with Vibi Anna, who she thought was Trixie, and now hungers for blood. 

Birth of the Equestrian Insurgency

After Canterlot fell to Line Ark, Rainbow Dash followed Twilight Sparkle along with Rarity (The remaining of the mane 6 loyal to Equestria) to assemble a fleet of Airships and Zeppelins which was to house the new Equestrian Insurgency, an Equestrian resistance movement constantly on the move in order to evade Line Ark, and to retake Equestria from them.  Rainbow Dash quickly rose to rank of Wonderbolts Admiral as she was the next best to replace the then demised Spitfire in addition to coordinated attacks against Line Ark which proved more effective than Twilight.  Twilight was so obsessed with the destruction of the Line Ark Alicorns, thinking that their demise would be the end of Line Ark.  Rainbow Dash on the other hand, knew Line Ark's motive was to abolish the Alicorn Princesses, and knew that the last thing they ever wanted was one to rule on their side.  Rainbow Dash knew it wasn't the Alicorns but the Line Ark Counsel-- General Fusion, Admiral Butts, Applejack and later on Trixie and the counsel's representative, White Glint-- that needed to be destroyed.  Rarity eventually paired up with Rainbow Dash influencing the Equestrians to deviated from Twilight's orders, and accept "Admiral Dash"  as their rightful leader.  Although Rainbow Dash saw Twilight as a friend, Twilight's pride in her genius was so great that Rainbow Dash could not make her notice that the Equestrians grew weary of her.  So rather than making Twilight realize that the Equestrians no longer followed her,  Rainbow Dash allowed Twilight to go off on her own suicide mission against Vibi Anna (by then Princess Anna) so that Dash could focus on the Line Ark Counsel and their armies.  Dash knew that neither Alicorn would come back alive, and allowed the two most powerful of magic users to each other's  demise; ironically, just like how Vibi accused Princess Celestia of trying to dispose her and Joshua O'Brien by arranging a battle between them.

This ingenious tactic to get rid of the greatest of magic users as well as every battle Rainbow Dash fought, won or lost made her undoubtedly Equestria's most powerful and influential pony.