Sagaru Yamazaki serves as a Shinsengumi spy and inspector, utilizing his deliberately plain appearance for covert missions. Born February 6, he shares a birthday with his historical namesake, Yamazaki Susumu. Before joining the Shinsengumi, Yamazaki was a delinquent known as "Mountain Zaki" (or "Mountain Killer"), sporting a green mohawk and leading a small gang. He reformed after a confrontation with Isao Kondō's group, intimidated by their strength and inspired by Kondō's wisdom, becoming Kondō's protégé. Specializing in surveillance and intelligence gathering, Yamazaki conducts stakeouts while consuming only *anpan* and milk—a ritual he believes appeases the "stakeout god" for success, despite disliking the food. He carries "Shinsengumi sausage" as standard equipment. His hobbies include badminton and kabaddi, which he often prioritizes over duties, incurring physical reprimands from Vice-Commander Toshirō Hijikata. Standing 169 cm tall with black hair, his ordinary looks aid espionage. His appearance has been altered comically or narratively, including forced hairstyle changes (afro, blond) and a temporary gender swap into "Yamazaki Taeko" during the Dekoboko Arc virus. His past featured the green mohawk. Key developments include: - **Shinsengumi Crisis Arc**: Uncovering an assassination plot against Kondō, Yamazaki was severely injured by Kawakami Bansai, who spared him to "listen to his song." Hospitalized and presumed dead by the Shinsengumi, his funeral received minimal attention. - **Timeskip/Silver Soul Arc**: After disappearing for two years, he resurfaced as "Mob Cop," a cyborg created in a clandestine lab with missile launch, beam attack, and cooking functions via his backside. He later regained his original body. Post-series, he could split into multiple clones with distinct personalities, including his pre-cyborg self, coexisting harmoniously. - **Romantic Subplot**: Spying on Yorozuya, he witnessed the android Tama fixing a store scanner. Her kindness moved him, leading him to abandon his mission and develop feelings for her. - **Character Poll Arc**: He conspired with fellow "plain" character Shinpachi Shimura to manipulate popularity rankings by inciting infighting among others, briefly achieving the top spot before rankings normalized. Relationships: - **Shinsengumi**: He shows unwavering loyalty to Kondō and Hijikata, enduring Hijikata's frequent physical punishments. His rapport with Sōgo Okita is indifferent. - **Shinpachi Shimura**: Bonds over shared "plain" identities, though Yamazaki is often more overlooked. - **Hattori Zenzō**: Collaborates occasionally, such as during a joint ninja license endeavor. Skilled with a sword (notably the Osafune Mark II), his primary strength is espionage. His unremarkable demeanor enables effective infiltration, evading even advanced surveillance like Oboro's crows. Post-cyborg enhancements expanded his combat capabilities until reversion. Trivia: - He holds a grudge over his "plain" reputation and absence from *Gintama* manga covers, per creator stipulation. - During a body-swap arc, his consciousness fused with animal droppings, and Sadaharu controlled his swapped body. - By the series' conclusion, his hair grew longer, but he remained dedicated to the Shinsengumi.