(Disclaimer: I don't own RWBY and Fate Stay Night.)
There was a unique Huntress who aspired to be a hero.
Heroes like those in fairy tales, wielding sorcery and accomplishing amazing deeds in their adventures, have become objects of reverence for slaying a mythical Grimm and rescuing lives.
More than anyone, she wanted to strive to become like a genuine hero, like the ones in the books.
Her dream was childish. Even as an adult, she holds into that dream; she was often called 'foolish' by her close friends.
It indeed was foolish - and she did not deny it. Foolish as it was, she has never come to hate it. Because her motivation never came from her satisfaction, nor through people's attention.
It was through the happiness that radiates from the people that fuel her ideal. She eventually realizes that each hero's noble title was bestowed upon them as a result of their trials and tribulations. Moreover, the protagonists of the books are always driven by some sort of motivation to accomplish their objectives.
Her motivation was simple - to become a hero that everyone deserves, a Hero of Justice. She promised that.
This simple promise, however, punished her every time she pursued her ideal.
If every person she has saved overflows her with pride, then every person she has failed overwhelms her with remorse.
Her mindset is admirable yet her guilt will never cease; every year, a village is destroyed, every mutilated corpse is buried by her hands every time she arrives late. It was her way of saying "I am sorry" to the deceased.
Moreover, she would sometimes experience burying children. She would always assume the age of each child she buried was something close to her daughter - making her drip tears of failure every time she could not save them, she would not cry for Grimm will notice... But their startled expressions; dried tears, and blood from their agony always strike a deep chord within her heart since she knows they died slowly and painfully, which a child shouldn't have experience.
The Grimms are indeed a horrible sadist that enjoyed the unpleasant emotions of people. They, who have lived among Humans and Faunus for thousands of years, never feel any sympathy for killing innocents, but instead, relish the anguish from the people like an aphrodisiac.
A cycle of evil that she wishes to break, many people would think it's impossible, but to her, the word "impossible" is merely a catch-all phrase used by those for a lack of determination. If it is really impossible, then she ought to at least slow the cycle, that is why...
-If she tried harder, fewer people would die and more people would be happy.
With determination, she will find a way to put an end to the Age of Grimm. With any mission she undertakes strains her eyes, arms, and legs - every day, she overworks her body to the point where her boss pressures her to take a holiday. Never had she taken any holidays once she has faced reality for the first time, the holidays were only reserved for her husband and daughters. She might be selfless but she has never taken it to the extreme because the conclusion would be to abandon her family for the sake of her ideology.
She would come to realize that her ambitions are a road to hell, she will have to go through the same scenario again and again if she does not arrive on time. Who'd have guessed that her own naive vow could be so painful? And yet, she couldn't hate it.
Of course, Her husband was understandably concerned. Every time she comes back home - she always comes back exhausted. Nevertheless, people's lives were always at stake; She couldn't stand the thought of the people's pained faces.
Therefore, she left with a meaningful farewell to her daughters, "promising" to return.
So she went to confront his boss's last task, which only she could complete. Stopping the root of it all, Grimm will eventually cease assaulting every village - every year.
She would confront the Queen of Grimm herself, Salem.
She already knew that Salem could not be killed, but she can be stopped. However, even with all her might, she unable to stop the Queen; Salem was even stronger than before she last fought her. She hated retreating, but she had no choice; with a bleeding body, bloody cloak, broken limbs, and a depleted Aura, it was a miracle that she can still run. She had no idea where to flee until she 'sensed' something above the cliffs.
That is when she met a miracle. A passive spiral of energy emerged from out of nowhere; it emitted so much energy that even a Grimm would not dare to go near it.
Somehow, she knew it is communicating with her, its intention, its purpose.
She was sick of blood deprivation, her bones were fractured, and she was losing her ability to speak clearly. She had to make a life-changing decision.
"...If doing that means to stop the cycle, then-
It was already improving her health and also saving her. Floating threads were embedding themselves in her clothing and body, creeping like poison but transparent to the naked eye.
She can feel in it her veins surging with power - the 'Counter Force' already knew her intentions...
-I accept the contract, give me the power to become a Guardian...!"
She was granted enough power to overwhelm any ordinary adversary. But her adversary was anything but ordinary; if she couldn't kill her, then she just needed to seal the Queen for life.
That she did, that came at a price, however.
The Queen has left a curse within her very soul - she did not know how to counter magic, so her body was starting to fail. Her limbs were lame, her sights almost failing, and her Aura could not be channeled anymore. However, if she falls right now, the end of Grimm will be for naught.
As a result, she forced herself to locate and evaporate any Grimmpool in order to achieve world harmony, for her to become a hero, a part of her was no longer necessary, for she has already been free from her own promise. She just desired to make the world a better place for her children.
She sought assistance from an old acquaintance, the Branwen tribe's leader. Her partner had the power to teleport to someone who is acquainted with her, but she was just as stubborn as she was. Her partner once called her insane, but after much persuasion, she agreed 'only' if she gave up her weapon, which she did.
The worldwide extermination took two years for the Grimm to vanish, the curse devouring her like a plague. Nobody knows of her accomplishments except for a certain bandit; normally, she should have died by now, but her pure will to uphold her family's 'promise' held her alive.
Yes, she wouldn't forget the promise she made to her daughters. It was the last promise she needed to fulfill after all.
She must disregard the looks and decline the doctor's request. Because of her injury, which was irreversible, everyone was attempting to keep her from seeing her family.
Nonetheless, when she eventually arrived at her husband's home, she would crash with a thud on the threshold.
She would faint from the curse at the most inconvenient moments as if the curse was stopping her from meeting her loved ones. Owing to the curse's agony, she was unable to express physical frustrations.
She didn't get to see them, but they did get to see her. At the very least, she held her promise.
I'm home... Ruby, Yang, Tai...
I'm sorry...
With that, she will finally be freed from the constraints of time itself and removed from the ring of reincarnation, moved to the Throne of Heroes, a place existing outside of both the World and the time axis.
Furthermore, she will be utilized as a mindless Counter Force. She will serve as the World's attack dog - never to be free.
That is how Summer Rose became a Hero, a Counter Guardian.
"Ruby, what do you want to be when you grow up...?"
"I want to become a hero like you mom! a hero of justice!"
Ah, how she wishes to change her daughter's mind...
A.N: I'm really sorry for re-uploading this, the previous one didn't feel emotional so I quickly rewritten Summers's tragedy with the help of my friends... Hope you like it...!
This is my first fanfiction! English is also not my first language, so I hope you go easy on me!