Kudou Shinichi's Father. He is a famous mystery writer. 'Night Baron' is a character from his novel. He apparently also has the same sharp mind as his son, pretty much like a detective, probably because his novels are all mysteries.

Yuusaku was already noted for his sharp intellect and deductive abilities at a young age. He met Inspector Megure and became a good friend and valuable adviser to him in solving very difficult cases. While he often assisted the police, Yuusaku's primary aspiration was that of a writer. Quickly attracting acclaim in his early twenties as a young novelist, he encountered the girl whom he resolved to marry: Fujimine Yukiko, an already famed and beautiful actress. While taking her out in an expensive restaurant to make his proposal, he was involved in a murder case which he solved brilliantly, and right afterward proposed to a startled Yukiko - which she accepted. (Twenty years later, his son Shinichi would become involved in a follow-up of the exact same case, but unlike Yuusaku he wouldn't be able to profess his feelings to his own love.)

Yuusaku possesses a very sharp intellect and observation skills, traits which his son inherited, though Yuusaku's own abilities remain more well-honed. He demonstrates in multiple cases an ability to operate one step ahead of both Shinichi and criminals, but he chooses to not get involved unless Conan appears unable solve the case alone in time to save the intended victim. His success as a novelist is to a large part based on his keen understanding of the criminal mind, as his most famous recurring character is a criminal. While he is an excellent author, he will occasionally blow off his editors in order to do other things, such as travel with Yukiko.

He is very laid back and calm, never seen to lose his temper. Some might think him too laid back, as he often took his son to crime scenes before Shinichi was eleven, and showed no concern over six-year-old Shinichi dragging Ran and Agasa into a potentially dangerous area of town to investigate a code. The only time he has been shown to be caught off-guard or stressed by a situation is after the false kidnapping, when Shinichi alerts Yuusaku's editors to his location and they force him to make up for missing his deadlines. His less tolerable personality traits include a certain cockiness and a very bad touch at making humor.

(Source: Detective Conan Wiki)