What are the main characters in the Brazilian cat written by Sir Arthur Conan Doyle?

In "The Brazilian Cat," a short story by Sir Arthur Conan Doyle, the main characters include Mr. James Hardcastle, a wealthy and somewhat arrogant Englishman, and his friend, the narrator, who recounts the events. Hardcastle becomes embroiled in a dangerous situation involving a mysterious Brazilian cat, which is actually a sinister plot involving a criminal. The story explores themes of greed and danger, showcasing Hardcastle's downfall due to his hubris and curiOSity.