Taishiro Toyomitsu, operating under the hero alias Fat Gum, holds the 58th rank on Japan’s Hero Billboard Chart. He possesses a shape-shifting physiology, toggling between a rotund form marked by a wide grin and compact nose, and a leaner, muscular build after releasing stored energy reserves. His signature costume combines black tactical pants, orange hooded gear branded with "FT" initials, metallic combat boots, and an eye-concealing mask, with early-career iterations incorporating forearm armor and less ornate lettering. Known for his insatiable appetite and affable personality, Fat Gum transitions from joviality to battlefield intensity when protecting civilians or allies. His partnership with law enforcement agencies provides expertise in criminal syndicate structures and forensic procedures, applied during high-stakes operations like dismantling the Shie Hassaikai yakuza group. This investigative acumen complements his combat tactics, allowing rapid analysis of enemy Quirks and tactical weaknesses. The Fat Absorption Quirk enables him to engulf targets within his corporeal mass and transmute absorbed kinetic force into amplified strikes. Sustained impacts fuel devastating counterattacks, though prolonged energy expenditure shrinks his bulk to a slimmer state. Despite his size, he demonstrates surprising mobility alongside crushing strength—able to crumple steel machinery—and endurance against concussive assaults. His "Fataxi" maneuver safely ferries allies within his pliable body during operations. Notable engagements include commanding interns Tamaki Amajiki and Eijiro Kirishima during the Shie Hassaikai raid, where he absorbed relentless blows from Kendo Rappa before channeling stored energy into a knockout punch that neutralized both Rappa and his shield-wielding partner, Tengai Hekiji. Though critically wounded, his calculated Quirk usage secured victory. He later mobilized in the Paranormal Liberation War, directing assaults on enemy bases. Based in Esuha City, his agency headquarters mirrors his iconic silhouette and functions as a training hub for protégés. Pre-series activities involved joint operations with Eraser Head against the Villain Factory, disrupting Trigger drug trafficking by raiding laboratories and clashing with entities like the synthetic villain Number 6. A staunch advocate for minimizing collateral damage, Fat Gum routinely interposes himself as a human shield. His mentorship philosophy—emphasizing mental fortitude—shaped Kirishima’s growth during the Shie Hassaikai conflict. Post-mission engagements, from medical recoveries to honoring fallen colleagues like Sir Nighteye, underscore his commitment to heroism’s communal ethos.