Lord Castlewood is a fictional character from the novel "The History of Pendennis" by William Makepeace Thackeray. He is depicted as a wealthy and influential nobleman, known for his charm and social status. His character often represents the complexities of aristocratic life in 19th-century England. In the story, Lord Castlewood plays a significant role in the life of the protagonist, Arthur Pendennis. His interactions with Arthur highlight themes of friendship, loyalty, and the challenges of navigating social expectations. The character serves as a reflection of the era's societal norms and the intricacies of personal relationships among the upper class.