Another challenge because I can't write will I'm at my relatives for Thanksgiving.
After escaping the Tower of Heaven, Erza still has no family, no food, no money, and no experience with magic. Hunger forces her to try to steal what she needs to survive, but she ends up targeting the wrong crowd, stealing from a small group of wizards. With the wizards angry enough to be prepared to use some rather extreme punishment, things don't look good for Erza.
Then a young man with scarlet hair appears, wielding swords and drives off the wizards before they can hurt the child.
Shirou takes Erza home with him, feeds her, and explains to her the differences between having magic and being a mage, and between having a sword and being a swordsman.
With the girl still weak, but too stubborn to stay still, Shirou offers to escort her to Fairytale and teachs her what little he knows of magic along the way, as well as how to use a proper sword.
Erza learns swordsmanship and reequip magic from the young man before arriving at the Fairytale guild, before he suddenly vanishes with no warning, leaving her on the doorstep of the guild.
It wouldn't be until later that she hears his name again, seeing it on a wanted poster. Shirou Emiya, the Wrought Iron Magus, an infamous vigilante.
Shirou would still be considered a third rate magic user in regards to pure power, which means Erza has a lot more potential than he had. Its from skill and resourcefulness that he hunts down wizards who use political status in order to act like they are above the law, such as the leader of the Phantom Lord guild.