Physical Description:
A lithe boy, one would assume him to be unassuming due to his stature. Smaller than the average of his age at 4'7", almost waif-ish, with the look of a rather harsh breeze could blow him away.
Large eyes akin to that of a doe, in the deepest of browns and framed with long eyelashes, a pale countenance that the sun has kissed with many a freckle. Caedmon could be a doll, or mannequin, with his silken tawny hair that coats the tops of his shoulders.
But the beauty besets fragility. Perhaps not of the physical sort, for his days were spent running his family grounds and skimming his knees, only for them to be fixed up near immediately by a parent or sibling. But internally.. that is where the cracks show.

Mental Description:
The first word to come to mind when envisioning Caedmon Thistledown would be mousey. A quiet, contemplative boy with plenty to say inside his mind, but little that ever spills from his mouth.
Due to his upbringing, he is quite bookish, though in his chest he often feels a pull for the outdoors. And while he is well-read, well socialised he is not. Aside from his parents, his siblings and perhaps a select few cousins, he has not been privy to the world of childhood adventure and socialisation. No best friends, no adventures in the woods and fields with a gaggle of children. As such, he is both utterly overwhelmed by and longing for the presence of the other students.
Due to this, his interests tend to skew towards magical creatures. Reading about them, of course, but also often spending his time in his family's kennels, which housed many a Crup. He is quite fond of creatures as a result, eventually preferring their company to that of even his siblings.


Biography:
The youngest child of the Thistledown family, and born more still than wriggling, Caedmon was always ... coddled. Drowned in healing magic whenever so much as a sniffle entered the manse. Bundled the tightest as a babe, ever in arms as a toddler. Weaker, physically, than his boisterous siblings and thus restrained from playing with them as a child.
The world, for Caedmon, was as small as the family's estate. Perhaps even smaller, on the days his mother, Eglantine, would fret and confine him within walls. On one hand, he cherished the love of his parents. But on the other, he craved what he could not have. From windows, he would often watch his siblings and their friends play, imagining he, too, had his bare feet in the soil.
When the Owl arrived, dictating his admission to Hogwarts, the house was ... tense. After a childhood of homeschooling and trying to experience the world through the written words of wizards more tenured than he, naturally there would be apprehension. To be away from home, away from the estate, for the first time. To live away for a good part of the year among strangers. Even with elder siblings currently enrolled, it was enough to turn his stomach.
Caedmon was resolute to ignore it. Even as his mind wandered towards potential adventure.
The months would come and go with the changing of the seasons, and the date would draw nearer. All the while, Caedmon would sit in the kennels, nose in books and a crup's head in his lap. Forced ignorance and heavy stares to all who would come to disturb his peace. That is, until the day came where his father, Anatole, would come and pick him up without a care in the world towards the boy's protests, and force him into action.

First Instance of Magic:
Longing.
Age five, knees pressed into the window seat's cushioned long enough to have them red raw. Palms against glass and smudging the shine. The world is vast. The world is tiny. The world comes down to his three siblings screeching and playing with their crups in the gardens, weaving through flowerbeds and fountains.
The boy wonders what it feels like. The spray of water, the scent of roses and wild blooms. Grass beneath his feet. Nothing akin to the room he inhabits day in, day out. With his mother reading her paper by the unlit fireplace, as she drinks her breakfast tea.
Caedmon's eyes close, and he wonders. He wishes. His heart racing in his chest, as somehow his nose smells the summer air mixed with the fountain's mist. As he feels petals brush against his legs, as-- he hears his mother gasp and rise from her chair.

The rest is a mess of chattering, shouting, as roses bloom from wood and fabric, and the air is wet with fresh water. Even as the boy is lifted and passed around for congratulations and cooing, his gaze remains fixed firmly on the window.