Just a short one-shot that popped into my head. It really is meaningless.
Disclaimer: I really wish I could say that I owned HP, but alas, *sigh*, that is not the case. J.K.R. owns this.All eyes turned as the eleven year old walked to the front of the Great Hall and sat on the stool to be sorted. Everyone in the hall was staring, you could almost feel the magical power radiating off of her. She smirked as the hat began to rummage through her mind, as though she knew some secret no one else did. "GRYFFINDOR!" The hat shouted to the hall. She walked calmly and slowly to her new house. This girl didn't look eleven; the confidence in her entire posture was much more than that of an eleven year old. It suggested age and experience.
"Potter, Harry!"
As the next name was called all eyes turned once again to the front of the room, this time exclaiming in shock at the figure who walked forward, and the girl was forgotten.
The first transfiguration class found the girl transfiguring her match into a needle before McGonagall had even finished explaining, without a wand.
The first potions class found her patiently explaining to Snape that even if Harry had merely opened his book, it wouldn't have done him much good, he would have had to read it to learn something.
That Friday an astonished set of twins found her sitting in the kitchens conversing with the elves in their native tongue.
The first flying lesson found her silently slowing Neville down as he fell, not that anybody noticed.
The night Harry first met Fluffy found her silently watching, ready to intervene if necessary.
The first Quidditch match found her staring silently at Snape, ready to take over if he failed to save Harry.
The first time Harry entered the Forbidden Forrest found her trailing silently behind, calling for Firenze when he found the unicorn – and Voldemort.
The time Ron fell in the chess game found her waiting patiently by his side while he was unconscious, making sure he was alright and waiting for one of them to come back. When Hermione came back she silently, invisibly, followed Harry.
The second time Harry defeated Voldemort found her sitting by his side, making sure he didn't die before Dumbledore arrived.
The next year found her walking around the school, listening for the basilisk.
The day Harry and Ron entered the chamber found her, once again, following silently and invisibly behind – calling for Fawkes when Harry first met Tom.
The year after that found her waking Lupin on the train as the dementor approached the compartment.
The first defense class of that year found her facing her worst fear – a miniature version of Hogwarts with all the students dead or dying, the castle itself in ruins.
The end of the third year found her following three students into the passage under the Whomping Willow, and then listening to the conversation that followed.
The first defense class of the fourth year found her not even responding when the Imperious curse was cast upon her.
The month before the first task found her hinting to Hagrid how much Harry enjoyed seeing dragons.
The first task found her watching over the Hogwart's champions as they battled said dragons.
The month before the second task found her hinting to Cedric that without Harry he would have lost the first task – badly.
The second task found her sitting on the opposite side of the lake from the spectators, sticking her head in every now and again to listen to the merfolk.
The third task found her flying invisibly over the maze, watching for Cedric and Harry, cursing when the cup was a portkey.
The time he returned from fighting the Dark Lord a fourth time found her bumping into Dumbledore, invisible of course, on her way to follow them, causing Dumbledore to see Moody taking his student away.
The first detention, and all the ones after it, Harry had with Umbridge found her, once again, watching invisibly.
The first DA meeting in the Hog's Head found her silently listening to everything Harry had to say – then signing the list.
The sixth year found her returning to Hogwarts once again to watch over her students, rushing Katie Bell to the Hospital Wing while Hagrid escorted the others back to the school.
The entrance of the death eaters to the school found her fiercely battling with them, putting up shields over all those on her side who had fallen.
The seventh year found her watching over the students when they were in detention – sometimes even distracting the teachers enough to take other students' place.
The DA meetings that year found her constantly consulting with Neville, Ginny, and Luna, planning how to save the students.
The Battle of Hogwarts found her throwing curses and shield charms left and right, hitting the death eaters and protecting many members of the Order and students from death.
Nineteen years later, as Harry said goodbye to his two sons as they boarded the train he noticed one of the fifth year Gryffindor prefect who looked rather familiar. However, he couldn't think of who it was. He knew he had seen her before, but he also knew he didn't know any of the prefects that year. She looked up, caught his eye, and gave him a quick nod before turning around and helping the students. And Harry, for some odd reason, knew it was fine – his kids were safe.
As he exited the station with his wife he forgot all about the girl – never to think about her again.