Fate/Stay Brockton Bay Backstory
Disclaimer: I do not own the characters or places depicted below. I only own the madness the mashed them together. If you sue me all you will get is my allergies.
A single change can have far reaching consequences. Take for example a change in the road maintenance schedule leading to Shirou taking a detour and saving one Bazett Fraga McRemitz from bleeding out. Of course this being Shirou he puts the remains/traces of a magic circle and an unconscious person bleeding from the lose of an arm and thinks sacrificial victim.
Unable to let someone die that he could save but knowing that he can not send her to hospital incase she reveals magic to the doctors he calls upon skills he learned in preparation of becoming an ally of justice known as first aid to slow the bleeding Giving him time to call upon the power of friendship in the form of Raiga Fujimura to save her.
A servant hands Raiga Fujimura the phone.
Servant: It's Shirou sir he says he needs a favor and that it is important.
Raiga takes the phone.
Raiga: Shirou my boy what's the matter you never ask for a favor?
Shirou: I need a doctor who can handle a lost arm and severe blood loss at the park as fast as possible.
Raiga: Stay there! I will be there as fast as I can.
Later after having one of his yakuza doctors save Bazett's life Raiga sits Shirou down to grill him on what happened. This results in a critical failure in Shirou's lying skills with him revealing the little he knows about the moonlit world to both Raiga and Taiga. While Taiga is stunned by this Raiga reveals he knew most of this from working with Kiritsugu Emiya and states his support of Shirou. Unfortunately due to a Yakuza political even due to happen next week they have to store the unconscious Bazett at Shirou's house where he tries to add to her protection in the form of an (extremely) basic magic circle. He is partially successful resulting in a charged circle that does nothing but emit tiny amounts of magic.
Que the standard Shirou introduction to the grail war. The morning after summoning Saber and extremely suspicious Taiga accidentally shoves Sakura into the same room as Bazett.
Sakura: Shirou why do you have an unconscious magus on an IV in your guest room?
Shirou: Wait their is a good reason… Wait you know about magic?
Taiga: What one armed chick is a Magus.
Saber: Master why was I not informed of this?
One confused and confusing conversation and a timeskip to after Shirou meets Kirei kotomine later Bazett wakes. After learning the situation, finding out just how weak her brush with death has left her as well as one of Shirou's meals later she decides to stay and advise Shirou (and eat his cooking). This completely derails the time line ending with an alliance of Shirou, Ilya, Berserker Sakura, Rider, Rin and Archer facing off with Kirei, Lancer and Caster who are holding Taiga hostage only to have the battle crashed by a pissed off Gilgamesh who immediately kills Archer. As thing get out of control Shirou gets the "brilliant" idea to try and use multiple Projected Fragarach against the grail system itself. Que a swilling hole in reality of doom later Shirou and his allies wake up in Brockton Bay several months before the events in worm minus Ilya and berserker..
They quickly determine that they are no longer in their own world. For some reason Bazett blames a guy she calls Zel. To help support themselves Shirou gets a job catering asian food. Rin and Bazett begin researching the difference between this world and theirs. After hearing about all the heros and villains it takes the combined might of everyone to stop Shirou from joining the Protectorate instead he tries to become a Rogue hero along Rin who joins him after reading about the loot laws and deciding it was an easy way for her to gain gemstones for her magics. Their attempts to be viewed as heros fall through when Taiga's attempts at using what she had learned from her grandfather to set up some fences to sell their loot results in a new gang that the PRT believes were led by Shirou's and Rin's cape identities.
While this is happening Sakura befriend Taylor but is unable to prevent the bullying from causing her to trigger. Shirou's catering job starts to unknowingly get hired by the ABB as it turns out that his cooking can calm Lung down even when he is in a bad mood and gets more bad news. This goes on to the point that the ABB begin to refer to him as the Dragon Chief making the Protectorate think their is a new cape on the scene that they have never seen.