Cassidy has spent her entire life on a tiny farm in the rural west of Ireland. This farm, unlike those of her neighbours, goes about things in a different way; magic has become a major part of the day-to-day operations there. Cassidy's great-grandfather Ashe was born to a lower class muggle farming family, but turned out to be the first Ashe invited to go to Hogwarts. After he had completed his education, and the farm was turned over to him, he neither wanted to resume a muggle way of life, nor did he wish to give up the stead that had been in the family for nearly a millenium. And so he went about the somewhat slow and tedious business of converting the small farm, to produce crops and raise livestock for the surrounding wizard community. This task was made somewhat easier, given that the entire farm was secluded from the others by a large grove of trees growing on three of the four sides. Still, anti-muggle charms were put in place to keep muggles seeing only an ordinary Irish countryside where the farm indeed stood.

Cassidy's mother, Orlath, hails from a long line of well-respected and well-off wizards (the McTaggarts of Dublin). She met and fell in love with Seamus while they were both at school (her in Ravenclaw, him in Hufflepuff), but they did not get married until many years later; the McTaggarts to this day do not fully approve of this marriage, and look down upon the poor, hardworking (if not entirely bright) Ashes. Cassidy's mother refuses to take any money from her family, not so much out of pride but out of a desire to prove to them that one can indeed survive on a modest income.

And so, Cassidy and her younger brother Quinn Riain, grew up healthy and happy, running through the fields, swinging from an old rope tied to the rafters of the barn, and always pitching in with chores. Cass has never had much pocket money and always has to get by with second-hand items, but she rarely seems to mind. She's proud of her family, and proud of the farm, and like her mother, sees no shame in living a thrifty life. Of course, that's not to say she would say no if her family were to suddenly strike it rich somehow, so long as it was through good, honest work.

The summer of her eleventh year, Cassidy got her letter from Hogwarts, as expected. She bid a somewhat sad farewell to her home and her family, and then took off, eager to see the school of which her parents had always spoken so much, taking along her new pet rat, Bonkers - a congratulations gift from her grandfather Ashe. In her first four years, she's worked hard and steadily. Not a natural scholar, she manages only to pass through her hard work, doing better in classes such as Care of Magical Creatures, and Herbology.

Although she's generally friendly and outgoing to all, she's yet to have a truly close friend with whom she can share everything.

Not exactly the bravest of sorts, Cassidy has had trouble dealing with all of the events surrounding You-Know-Who and his followers. Her one saving grace, though, was her ability to remain somewhat oblivious at times. Whenever things became too much to handle, she would retreat quietly to her own little world, doing her best to keep busy and pretend everything was all right. After all, it always seemed to turn out that way in the end. However, the loss of Cedric in her third year dealt her a heavy blow, as it did the rest of her housemates. She could hardly pretend it hadn't happened, but she still toiled away, doing her best to keep busy and keep her head down.

With the appearance of Umbridge, Cassidy was rather shocked to watch her beloved Hogwarts turned into such a twisted version of its former self. She got told off a few times for speaking out of turn in her first DADA lesson, but managed to avoid getting punished any further than that. She quickly learned to just mind her business and keep her mouth shut as best she could, sticking largely to her own common room after and between classes. For the first time since she began at Hogwarts, Cassidy was surprised to find herself eagerly awaiting summer holidays and escape from school. And so, heading into summer holidays, the young Hufflepuff is a little quieter and more somber than she once was.