I hope you all enjoy the story Here's the disclaimer: I own only the ideas you do not recognize.
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Harry and Neville were considered weird. They had always been a little strange but they were considered exceptionally weird once they entered Hogwarts
The first thing strange about them was that they entered Hogwarts at 15 years old, there owl year. The reason for this was that their parents had made enemies. They had made so many enemies that it was not safe for them to be so open. After Harrys parent's death and Neville's parents being tortured into insanity around the fall of Voldemort which happened when they turned fifteen, they could finally go to Hogwarts. The problem was, they never quite fit in. It was strange for people to enter the school at fifteen not eleven.
The second strange thing was that they had very minimal contact with people their age. The truth was, they were the only friends each other ever had and so they formed a very strong bond together. They did not quite know how to relate to the rest of the world.
The third of many strange things was their intelligence. They knew something about everything. They were taught by the best aurors and unspeakables in history. They had spent most of their lives locked in a large house with an even larger library. Left to do their own things, which normally involved consuming the books.
They did manage to make a few friends, Luna Lovegood who was strange in her own right. Colin Creevy who was the creepy kid with a camera. The Weasley Twins who found themselves with a challenge.
They however found more enemies with people trying to bully them. They were not ones to take it laying down, but it was the way things were.
Their graduation was a long-awaited day. It was finally there. They took their diplomas and left. The year after, Colin and Luna disappeared with them.