Mycroft Holmes is the older brother of the legendary detective Sherlock Holmes, a character in the fictional stories created by Sir Arthur Conan Doyle.
According to the stories written by Doyle, Mycroft held an undisclosed position in the British Government, and was known for collecting all sorts of information, no matter how minute or inconsequential. Unlike his younger brother, though, he lacked the will to follow through with his theories and observations. Doyle best described Mycroft as being a warehouse of information. He was large and tall and quite sedentary in both appearance and mannerism. He was also the co-founder of the Diogenes Club, a rather "scandalous" gentleman's club for Victorian England.
Champions Online Universe
According to Major Xavier Cross of the United Nations Tribunal on International Law, Mycroft Holmes was in fact a real person, and he did possess a finely-detailed mind and an incredible sense of memory in terms of collecting and retaining information. So much so, in fact, that he was often asked by Scotland Yard for assistance in some of their cases. Initially this assistance was in background information, however he could not help but be drawn into helping resolve cases himself.
Unfortunately his connection to the British Government, and specifically to the Royal Family, served more as a hindrance to having a more active role as a detective. In addition, his hyper-sensitive sense of observation and deduction came at a cost of some of his other mental facilities, including remembering basic details such as putting on clothes before going out in public. On more than one occasion he had welcomed visitors in the nude, which, combined with his large and unappealing frame, did more than just startle some people. The idea of such a person assisting with criminal cases, and the potential political scandal that would result from it, was seen as the chief reason why Scotland Yard was loath to ask more from him other than for background information.
As a way to be noticed for his detective work, Mycroft retained the services of Sir Arthur Conan Doyle to write fictionalized accounts of his new "hobby" as a detective. Doyle came up with the idea of a odd detective team, with himself as Doctor Watson, and Mycroft being portrayed as a fictional younger brother Sherlock. With an occasional mention of Mycroft having a more "sedentary" role in the books, Doyle was able to transform Mycroft's real investigative experiences with Scotland Yard into larger-than-life classics.
Connection to Project Mycroft
Xavier Cross learned of Mycroft Holmes while training with U.N.T.I.L. on mastering his pyrokinetic abilities. He was fascinated by the idea that man such as him could rise to a level of importance without public attention and still carry tremendous respect.
For reasons that have yet to be explained, Cross used the little-known story of Mycroft Holmes as the inspiration for Project Mycroft, a classified U.N.T.I.L. intelligence-collecting program.
(Please see Mycroft's Wikipedia entry for more information.)
Mycroft Holmes was mentioned in "Future's Guardian" #3.