Dr. Henry Jekyll and his alternative personality, Mr. Edward Hyde, is a fictional character in Robert Louis Stevenson's 1886 novella" Strange Case of Dr Jekyll and Mr Hyde". He is the title character and a friend of main protagonist Gabriel John Utterson.

Dr. Henry Jekyll feels he is battling between the good and evil within himself, thus leading to the struggle with his alter ego, Edward Hyde. He spends his life trying to repress evil urges that are not fitting for a man of his stature. He develops a serum in an attempt to mask this hidden evil. However, in doing so, Jekyll transforms into Hyde, a hideous creature without compassion or remorse. Jekyll has a friendly personality, but as Hyde, he becomes mysterious and violent. As time goes by, Hyde grows in power and eventually manifests whenever Jekyll shows signs of physical or moral weakness, no longer needing the serum to be released.

John H. Watson, known as Dr. Watson, is a fictional character in the Sherlock Holmes stories by Sir Arthur Conan Doyle. Yury Andreyevich Zhivago is the title character and protagonist of the novel "Dr. Zhivago". Dr. Julius No is a fictional character and the major antagonist in the 1958 James Bond novel and its 1962 film adaptation "Dr. No".

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