It coiled around him, through him, in him, not that he ever noticed

A wizards magic is partially alive, and gains traits from its host. This particular magic had bonded much closer than a standard wizards ever would, its power far outstripping that of a normal wizard yet it was rare that anyone would ever notice.
For like its owner, this magic primarily hid, resting in the bones, the marrow, the flesh, and letting only a portion of its power show lest it be rejected as something unusual, something different… something like a freak.

Harry Potter sat in his cupboard, wishing somebody, anybody would come and take him away from here. He had been beaten, again, because something strange happened around him. Why this was his fault, he didn't know, but he did know that strange things tend to follow him around. This time a teacher was yelling at him because he had shown up to school dirty and muddy (His cousin, Dudley, had been playing his favorite game "Harry hunting" and pushed him over repetitively) He felt something lash out at his antagonizer and the teachers hair had suddenly turned a bright, ugly blue.
"Am I really a freak like they say?" thought little Harry, then he curled into the corner and desperately tried to forget everything that had just happened. As always, it worked. After all, bruises, sprains, injuries, they all healed so fast that it was quite easy to ignore and forget that they every happened, right?

Years past, and Harry had the best thing, every happen to him. He was taken to a school, a magic school, a wonderful school! It was called Hogwarts. A silly name, to be true, but he could get friends here, ones that Dudley wouldn't drive off, where he could be normal and he wouldn't be alternatively stared at and ignored as he was currently was. All he could hope was that he prove himself to everyone that he was good, and the same as all the rest of them. Then they would include him, because he wouldn't be a freak like he was at his old school.

His magic, feeling the demands of its other half, stayed hidden. Luckily for Harry, even with his magic hidden it radiated enough power for him to cast spells like the rest of his class.

"WHY!" roared an older Harry Potter who was safely locked in to the confines of his room. His Godfather, Sirius Black, had just been killed because he, Harry Potter, so called "Boy who lived" was stupid and weak, running head first into a trap and then lost spectacularly in the resulting fights against the death eaters.
"Never again, I swear, never again!" Harrys voice dropped down, as he swore oaths, bindings, promises, to himself and the air around him. He worked himself into a rage, beyond a rage. The comforting aura of normality he restrained himself with shook, as he called himself to more power than ever before, then refused to loose it.

Then He snapped.