When Fergus Kilgore met Regina Sallow, he was researching the Brigalow tree in Northern Australia, looking for new possible woods to use in wands and the different effects they may have. Sallow was a muggle, taking a gap year before college. They met at a friend-of-a-friend's party and immediately hit it off. They moved in together and Casper was born on October 22nd, 2008.

Less than a year later, Casper first showed signs of magic when his mother was attempting to feed him brussel sprouts. When he refused and turned the vegetables on the spoon into bubbles, Regina was understandably freaked out and demanded an answer from Fergus, who saw this as a remarkable feat for such a young wizard. They argued all night and by morning, Regina was gone.

Devastated, Fergus dropped Casper off in the hands of his older sister Hecabe and her wife Lidiya. Hecabe, like Fergus, had been a Ravenclaw in school and worked in the local library. Lidiya Petrovyik was a muggle whose sister, Sasha, turned out to be a witch who attended Hogwarts. Sasha became friends with Hecabe who in turn became friends with Lidiya and married after finishing school. They were delighted, to say the least, to welcome Casper into their home (apartment) in Blackpool.

As Casper grew up, he was given stacks of books, preparing him for his life as a wizard, and horribly knitted sweaters, both he accepted with stubborn politeness. Hecabe taught him to play piano, but he's very bad at it. Lidiya taught him to knit, but he is also terrible at that. For his ninth birthday he wanted a broom and instead opened a wrapped up bike that morning. He soon came to enjoy his gift, biking across town in his free time. Casper was diagnosed with Asperger's a few months after his birthday, but he tries to not let that interfere with his life. He was forced to attend muggle school until he received his letter from Hogwarts, walking the line between the magic and muggle world.

Throughout his eleven years, Casper has seen very little of his dad, as he only visits once a year at most due to his line of work, traveling across the world, researching trees to be used for wands. He's never met his mom, but Fergus gave him a few of his old Polaroids of when they were together, which now hang on the wall of Casper's room. He holds some resentment towards his parents but he does daydream what it would be like to live with them. That aside, he loves Hecabe and Lidiya very much and enjoys their company, no matter how embarrassing they can be.