There are many different kinds of pain...
He'd known it would hurt, of course. His father had warned him beforehand, promised him if he was brave, it would be over quickly. His mother had tried to comfort him, hugging him close. He'd smelt lavender from the sachets in her clothes-drawers, vanilla from her baking, and the slightest tinge of salt. She took such care never to cry where he could see her. He hadn't the heart to tell her he could smell the tears as they formed...
As the sun set, they left him in his reinforced cellar. The door had two bars that slid across at the top and bottom, plus an extra padlock, to be safe. He'd whimpered, once, as their footsteps faded and night began to fall.
He'd known it would hurt. But what does a six-year-old child know about pain?
How do they cope, alone and abandoned in the dark, as their bones creak and stretch into agonisingly unfamiliar shapes? What can they do when their skin sprouts fur, burning until they try to peel it from their flesh with their fingernails, just to make it stop? What can you say to such a child, when their blood feels like molten iron pounding down their veins? Do you comfort them, as out of the depths of their mind a foreign consciousness uncurls and readies itself for the hunt?
Or do you run screaming from this monster, that once was a human child?
When his parents returned by the light of the sun, he was unable to even tremble. The wolf had been infuriated at being denied its right to prey, and had turned on its host instead. His small body was battered, legs and arms mottled with bruises only beginning to show.
The pain never diminished.
Every month, as the full moon rose, his body and mind were wrenched apart by his curse. His limbs screamed in agony as his mind was subjugated by the wolf's instincts and he was forced, in lieu of other humans, to attack himself.
The tiny cellar was enlarged over the years as both he and the wolf grew larger. A small barred window was added; sometimes, the wolf was content just to howl at the moon. It didn't happen very often.
The Shack was like a mansion, when the time came to go to Hogwarts. The first full moon in September the wolf had spent the whole night exploring and marking it, leaving him with only the phantom pain of the shift to contend with.
He'd transformed hundreds of times, by now, and the pain of transformation was a familiar torture to him. But this night was different. This night, the wolf was content. The only injuries he would sustain were from careless leaps and misplaced branches, not a malevolent devil turning on its own flesh.
As the moon shone down on a certain magical forest, its shadows concealed a motley pack. The silhoette of wolf, rat, dog and stag reflected briefly on the rippling lake before they vanished into the trees, leaving only their pawprints behind...