Mycroft Holmes in "The Greek Interpreter", his blundering approach to the case nearly costs the client his life. Mycroft resembles Sherlock, but is described in "The Greek Interpreter" as being "a much larger and stouter man". In "The Bruce-Partington Plans", the following description is given: Mycroft spends most of his time at the Diogenes Club, which he co-founded. He is the only character to refer to Sherlock exclusively by his first name. Mycroft Holmes has been portrayed many times in film, television, and radio adaptations of the Holmes stories. The character has been used many times in works that are not adaptations
Mary Russell (character) as well as meeting Holmes, Russell prepares for and eventually passes the entrance exams to Oxford University, where she reads chemistry and theology. In addition to Holmes, who acts a mentor and father substitute early in their relationship and eventually becomes her husband, Russell becomes close to other characters from the Holmes canon: she considers Mrs. Hudson, who has accompanied Holmes to Sussex as his housekeeper, to be a mother figure, and she refers to Dr. Watson as "Uncle John" and Mycroft Holmes as "Brother Mycroft." She is also close to her farm manager Patrick and tends to make friends