Tyador Borlú is a fictional character from the novel "The City & The City" by China Miéville. He serves as a detective in the city of Besźel, where he investigates a murder that crosses the boundaries of two overlapping cities, Besźel and Ul Qoma. Borlú's work involves navigating the complex social and political landscape of these cities, where citizens must consciously "unsee" the other city to maintain order. His character embodies themes of perception, reality, and the nature of borders in a unique urban setting.