As Chief of the War Office's Intelligence Branch, Mycroft Holmes oversees Britain's covert operations of national interest. He directs MI6 and manages highly discreet assignments, commanding operatives such as Albert James Moriarty. Physically mirroring his brother Sherlock with dark blue hair and eyes, Mycroft stands 188 cm (6'2") tall, maintaining a stoic expression and shorter hairstyle. Occasional subtle smiles punctuate his reserve. He co-founded and frequents the Diogenes Club, adhering to a meticulous daily routine. His working-class maternal lineage shaped childhood Cockney accents for both brothers; though Mycroft refined his speech, he retains pride in these roots. Despite sparse documentation of his upbringing, he shares a competitive yet protective dynamic with Sherlock, balancing professional clashes with unwavering familial loyalty. Functioning as the government's intelligence "clearinghouse," Mycroft processes cross-departmental data to advise policymakers, wielding exceptional deductive and strategic abilities. His INTJ personality prioritizes logic, independence, and long-term planning, while his Enneagram Type 5 traits manifest as analytical detachment, thirst for knowledge, and preference for solitude. Privately sentimental, he masks this beneath professional reserve. Disciplined and routine-bound, he occasionally takes calculated risks for national security, disdaining inefficiency and idiocy while favoring black coffee. Personal quirks include a messenger pigeon named Charles Dickens—affectionately called "Charlie"—and dedicating 30 minutes daily to managing his wavy hair. Within the narrative, he navigates alliances with figures like Albert Moriarty to reform Britain's class system, containing the Moriarty brothers' extreme methods. He delivers critical support during crises, safeguarding Sherlock's possessions during his absence and intervening in the Reichenbach Fall incident, stabilizing the nation through overt authority and covert influence. His development reveals latent emotional depth, particularly regarding Sherlock's safety. Initially unflappable, he demonstrates vulnerability when family or national interests are threatened, cementing his role as a stabilizing force in the series' exploration of justice and societal change.