PonyPOVWorld Build Rainbow Dash/Princess Fidelitas

Pony POV World Building Rainbow Dash/Princess Fidelitas.

Princess Fidelitas is the Alicorn form of Rainbow Dash. 

Princess Fidelitas' Tarot is the Ace of Swords. 

Her Concept is both loyalty, AND the breaking of cycles. 

Nature's Law concepts as a general rule nearly all have a ying-yang traits to themselves (Luna being the goddess of dreams AND nightmares, and Rota Fortuna being of both fate AND free-will). 

Concepts are not rulers, dictators, kings, queens, or a ' cosmic upper class.' Just as the elder concepts are the foundations of the Pony POV verse realities, the concepts they've given birth to function as its pillars. And just like pillars they are TRAPPED in these roles, it is impossible for them to suddenly simply decide to cease their job. 

This means, that if Fidelitas were to enter a world line that was in a time loop, JUST BY EXISTING THERE she would cause that world line to become a normal linear one. It's not something she could simply CHOOSE not to do, it's what she is, it's not something she can suddenly chose not to be. (If she were to be assimilated into that reality, then the loop would be RETROACTIVELY erased and have never occurred since concepts are timeless). 

In other words, ground hog day loops are impossible in any reality Princess Fidelitas is in! Whether she likes it or not. 

She can also basically sever someppony who have leveled up to a million using time loops, from all their experiences and power-ups except the loop they're currently in, basically resetting them to what they were at before. 

Princess Amicitia's actions basically prevent ANY new Nightmare Eclipse from EVER existing in the pony pov verse timelines EVER AGAIN. 

Princess Fidelitas prevents a similar SITUATION as the one that brought Nightmare Eclipse into existence in the first place from ever happening again. 

This also means that the pony pov reality functions on the Many Worlds theory of time travel at the most extreme  (creating a NEW reality by entering the past), or that time is immutable at BEST (meaning any changes you've made to the past were made before you ever went back to the past), but time travel can NEVER EVER actually alter the current reality you're in.

It's possible that Princess Fidelitas is in fact a Obvious Rule Patch on reality to prevent the true horror of Dark World from happening again, ironically, for all of Fidelitas' dislike of being used, this is something if told she's EAGERLY and WILLINGLY embrace. 

She was basically born with abilities tailor made to negate the powers and abilities of a new Nightmare Eclipse if one EVER DID come about. And this is NOT getting into the side of her powers that come from being the goddess of loyalty.

Because Dark World!Nightmare Manacle Rainbow Dash ran for it the moment she'd ascended into Princess Fidelitas, and didn't spend the eons inside Fauna Luster learning to adjust to her new existence, her abilities aren't at the 100% they could be like Princess Amicitia's during her visits to the Grim Dark Worlds. Meaning if she had stuck around to learn more about her new self first, she'd have likely been a much bigger help to Equestria in its current state of need. 

Also an important world building note, Queen Libra is NOT Rarity's 'normal' Alicorn self, this form as unique to Dark World due to the unique happenstance that existed there.