Togashi Genji presents as a fiercely determined individual, readily confronting powerful opponents despite the odds. His appearance is marked by a distinctive school cap (a memento from his deceased brother), long disheveled black hair, a pencil mustache, and a scar over his left eye. He typically wears an unbuttoned Otokojuku uniform, bandages on his wrists, and a knife tucked into his waistband. Later appearances show him adopting a professional suit and shorter, combed-back hair, though he reverts to his uniform during conflicts like the war against EXP.

His background begins with his father, Togashi Genzo, a navy pilot and wartime comrade of Edajima Heihachi. After Genzo's death on Saman Island, Edajima visited the family. During this visit, Isa Takemitsu took Genji hostage, threatening his life to force Edajima to reveal an atomic bomb's location. Genji intervened by throwing a toy airplane at Takemitsu, enabling Edajima's counterattack. Following his mother's subsequent death, Genji was raised by his older brother, Togashi Genkichi. Genkichi enrolled in Otokojuku but was killed three years later by Dokugantetsu and Senkuu during the Great Trembling Conquest of the Unified Eight. Mistaking Daigouin Jaki for his brother's killer, Genji vowed revenge and enrolled in Otokojuku to find him.

As a first-year student, Genji frequently clashed with instructors and endured severe trials. He avoided forced seppuku by hiding a kitten in his shirt and proved his resilience in the Oil Bath challenge. He participated in the "Slash-a-Mole" duel against Maruyama, catching a sword blade with his teeth, and aided in the Head Seal ritual targeting Edajima. During Akashi Gouji's Reinstatement Ceremony, he narrowly escaped a guillotine execution thanks to Momotaro Tsurugi's intervention. In the Killoseum match, he attempted to shoot Akashi with a stolen pistol; Akashi sliced the bullet and seemingly mortally wounded him, but Genji survived using chicken blood as a decoy. He also fell victim to a scam involving an elderly woman posing as his mother, though he later rescued her from yakuza debt collectors. His experiences extended to the Ocean Island Tour, enduring Monk Onitako's "Human Watermelon Bash" and participating in Captain Ahab's hunt for Moby Dick.

Genji employs the Brawler Killing Style, emphasizing street-fighting tactics and survival instincts over formal martial arts. Key techniques include the White-Tooth Blade-Catcher (catching blades with his teeth), the Midair Double Kick (a spinning aerial kick), the Ball Crusher (targeting an opponent's testicles), the Volunteer Bombing Kill (a suicide charge with dynamite), and Blood Battle Reinforcement (carving the character for "battle" on his chest to bolster allies). He also performs combination moves with Toramaru Ryuji, such as the Boar Leaping Jumping Body Cannon (using a rubber slingshot to launch Toramaru) and the Great Fart Cannon Human Wheel (rolling while clasping ankles to execute tandem attacks).

During the School Festival, Genji endured the "House of Fists," allowing spectators to punch him for a cash prize, and later joined a rugby match against the Kanto Great Student Alliance. In the Four Great Trials of Terror, he represented Otokojuku against the Gogakuren, battling Hien at the Dangai Chuurankan (Violent Midair Cliff Gateway), a suspended rope fight on Mount Fuji's Wall of Dangling Severity. His character evolved from a serious fighter to comic relief alongside Toramaru, though he retained his bravery in combat. Across various arcs, including the Dai Ishin Pa-Lien Seiha and Battle of the Seven Tusks, his determination and loyalty to allies remained central, often involving high-stakes survival scenarios.