Matthew Clairmont is a fictional character from the book series "All Souls" by Deborah Harkness. He is a 1,500-year-old vampire and a brilliant scientist, specializing in genetics and biochemistry. His character is known for his deep intellect, charm, and complex personality, which often leads him into conflicts with both humans and supernatural beings. In the series, Matthew is also a member of the Clairmont family, a prominent lineage of vampires. His story intertwines with that of Diana Bishop, a witch and historian, as they navigate their unique abilities and the challenges posed by their different worlds. Their relationship is central to the narrative, exploring themes of love, power, and identity.