Shû Tsukiyama, heir to the wealthy Tsukiyama conglomerate, attended Seinan Gakuin University studying Social Welfare. Operating as the infamous ghoul "Gourmet" in Tokyo's 20th Ward, he selectively hunted humans meeting his refined palate and ran the Ghoul Restaurant under the alias "MM." His obsessive desire to consume Ken Kaneki led him to lure Kaneki to the restaurant and kidnap Kimi Nishino to manipulate Nishiki Nishio. After a near-fatal defeat by Kaneki and Touka Kirishima, he survived through autophagy, consuming his own flesh. Tall with striking Western features often described as model-like, Tsukiyama dresses in flamboyant European attire and wears a crescent moon-shaped mask. His appearance deteriorated severely during a two-year depression following Kaneki's presumed death, leaving him emaciated with unkempt hair and nails. He recovered rapidly upon learning Kaneki lived, resuming meticulous grooming but with a more subdued demeanor. Initially narcissistic, manipulative, and emotionally volatile, Tsukiyama prioritized gourmet experiences and interlaced his speech with French, Italian, and English phrases. His obsession with Kaneki shifted from predatory fixation to genuine loyalty after joining Kaneki's group post-Aogiri Tree arc. His depression involved violent outbursts and loss of kagune control, worsened by hereditary factors. Post-recovery, he showed humility, remorse for endangering his servants, and dedication to protecting others. He treated his human friend Chie Hori as a "pet" yet valued her deeply, while his servants, especially Kanae von Rosewald and Matsumae, displayed unwavering devotion despite his instability. His koukaku-type kagune manifests from his right shoulder blade as blade-like structures for offense and defense. During mental breakdowns, it spiraled out of control, resembling a kakuja. Classified as an S-rated ghoul, he was notably vulnerable to blood wine intoxication. Tsukiyama aided Kaneki's group against Aogiri Tree and Doctor Kanou but attacked Kaneki during the Anteiku Raid, believing his return suicidal. After Kaneki's memory loss and reappearance as Haise Sasaki, Tsukiyama's depression led to gluttony and self-destruction until Kanae revealed Sasaki's identity. He then sought to restore Kaneki's memories, though Touka Kirishima obstructed him. During the Tsukiyama Family Extermination Operation, he escaped with family sacrifices, including Kanae's death. He later joined Goat as a direct subordinate of the One-Eyed King, participated in the Rushima Landing Operation and Dragon War, and co-founded the United Front with Kazuichi Banjou and Ken Kaneki six years post-war. Leading the Tsukiyama family and United Front in later years, he showed protective yet unsettling interest in Kaneki and Touka's daughter, Ichika. In the spin-off Tokyo Ghoul PINTO, set during his high school years, Tsukiyama allowed Chie Hori to photograph his hunts, forming an unconventional friendship instead of killing her. His gourmet pursuits and popularity with female classmates continued alongside disdain from male peers.