K.S. Marsden is an internationally best-selling author of Fantasy and Urban Fantasy novels, known for creating thrilling adventures filled with magic, witches, monsters, and unforgettable characters. Based in Yorkshire, UK, she has made it a personal mission to ensure her stories either take place in Yorkshire or feature Yorkshire characters, bringing a distinct sense of place and personality to her books.

She is the best-selling author of The Northern Witch Series, an LGBTQ coming-of-age Urban Fantasy series following Mark, a teenager whose life becomes far more complicated than he ever expected. Mark was always written as a gay character from the very beginning, and rather than focusing on a coming-out story, K.S. wanted to explore what comes next: a character already comfortable in who he is, thrown into a wildly entertaining world of witches, danger, friendship, and adventure.

Her debut Witch-Hunter Series remains especially close to her heart. Fascinated by witches from a young age, K.S. naturally found herself writing about them. Alongside fast-paced action and magical battles, the series explores ideas of heroism and morality, questioning whether the so-called "good guys" are truly good. After all, from the Shadow Witch's point of view, Hunter and his colleagues might look like the villains.

K.S.'s Lost Soul Series is a love letter to the fantasy stories that shaped her childhood, particularly The Chronicles of Narnia. She wanted to create a world where a person's beginnings do not define their future — while also making room for evil unicorns, good monsters, and a fantasy world much larger and more complicated than the human characters first realise.

Outside of writing, horses have always been her other great passion. She spent much of her twenties working with horses across the UK and Ireland, and now lives back in her hometown of Doncaster with her horse, Mouse, and her very spoilt spaniel, Bailey.