The present day:
The Sunlit Blade looked at Twilight, unshed tears in her eyes. “By the time reinforcements from the Berryville abbey had arrived, it was too late. I was the lone survivor of what happened, and I know why – it wasn’t a courtesy that he saved me; no, it was a different sort of cruelty. The shame of knowing that everypony in the building had died because of my well-intentioned but ultimately damning treachery, and my naivety at believing that an innocent would be locked up in a remote place so heavily-guarded.”
“It must have been hard,” Twilight asked her.
“Oh, not as hard as what was to come: once they realized I was alive, I was transferred to the abbey in order to finish my healing. Shortly after that, I was moved to its gaol. After a few days, I was given a choice: be a huntress for the Order, in the name of the Princess, to forever spend my life hunting down evils – and especially the evil I had loosed…or to simply walk away, forget about it and move on with my life.” The answer was thick on her tongue. “There was no choice, really.”
“There is always a choice,” Twilight told her.
The Sunlit Blade cackled at that. “Oh, how I wish there was, your highness! But you who have faced Nightmare Moon, tell me true: had you failed in that task, could you have left things unfinished? Could you have just walked away, knowing what you’d done and the horror you unleashed? Could you have?” When the young alicorn stood there without an answer, the aged mare nodded in sympathy. “As you can see, there was no choice, no choice at all.
“After that, I gave up my life, my dreams and hopes. I swore an oath to the Celestines to put right what I had done wrong. And with that, they sent me to work with the greatest of their warriors, a mare only known as the Sunlit Blade. I would study under her and become her apprentice, and in time I would eventually become the Sunlit Blade herself.”
“And your real name is?”
“Irrelevant, your highness. The vain, flighty filly I had once been is long dead – and she deserved to die for what her foolishness had done. The day I swore an oath to the Celestines, I became the Squire, and was sent to a small home in the Badlands to train with my mistress, the then-Sunlit Blade. And for years I did that, learning every combat art there was and every magic that was possible for a pegasus such as I to master.” The mare sighed. “It was hard – very hard. Since time immortal, the Sunlit Blade and her Squire had always been earth ponies, hearty and battle-hardened, ready to take up the worst the world would throw at them, because they needed to be able to withstand the punishment. I had not the grace and knowledge of a unicorn, nor the strength and endurance of an earth mare.
“And yet, I persisted because I needed to. Because the world is a cruel and harsh place and monsters lurk in every shadow that nopony dares to approach. But somepony had to, and that was both my mistress and I.” She chuckled. “As a filly, I had dreamed of cotillions and lace, of frills and smiles. Now, all I know is banners and pageantry, blades and steel. And I am content with that, for the most part…if it had not been for my failure and the loss of my own Squire.”
“Your loss?” Twilight asked.
The Sunlit Blade nodded her head ever so slightly. “Twice, in truth. The second one is…well, she is of no importance. But it is the first one, my first Squire that I must tell you about, for she is my failure and the sin I must atone for.” Despite her age, she looked at Twilight with her blood-red eyes, a gleam in them born of a desperation to bare her soul to the young alicorn.
Twilight nodded. “Please, go on.”