Yuzuru Ema operates as a B-rank Sniper in Border’s Kageura Squad, previously an A-rank agent. His light skin and average build accompany thick eyebrows and medium-length, disheveled light brown hair that often falls into his green eyes, creating a youthful impression that occasionally misleads observers about his age. Casual wear typically involves plain dark long-sleeved shirts under open light sweaters, while his official uniform features a double-breasted black military jacket with five vertical buttons and Kageura Squad logos on the sleeves, gray cargo pants, and black Wellington boots.

Ema maintains an aloof, quiet demeanor but delivers blunt remarks when irritated, openly declaring dislikes—such as his direct criticism of Masataka Ninomiya. Exceptions arise concerning Chika Amatori: he flusters visibly when others hint at his feelings for her and exhibits protectiveness mixed with jealousy, particularly displeased when others discuss her reluctance to shoot people. This protectiveness ties to his rejection of Border’s devaluation of non-combat agents, a stance influenced by admiration for his sole mentor, Hatohara. His bluntness sometimes borders on unintentional rudeness, like implying Tamakoma Second could only beat his squad if they underperformed.

He deeply respected Hatohara despite originally being designed as an older character disliking Osamu Mikumo. Early complacency from high solo rankings led him to neglect training and combat logs, but his desire to protect Chika ignited interest in the away mission. This shifted his approach, prompting serious Rank Wars participation and a vow to teammates that avoiding combat against groups like Suzunari First would be unacceptable slacking. His sniper skills include confident assertions that follow-up shots won’t miss after initial failures.

Trivia notes his name’s homophonic link to "yield or give up," referenced by teammate Hiro Kitazoe regarding Ema’s early match-throwing intent. Preferences include curry, cream stew, teammates, and his mentor. Development shows his protective instincts evolving from possessiveness over Chika into constructive support, like offering tactical help. He challenges Border’s agent assessment metrics, arguing that refusing to shoot humans doesn’t diminish worth—a perspective rooted in Hatohara’s experiences. Key quotes include protecting Chika from Hatohara’s fate and claiming victory regardless of numbers. The author describes him as an innate genius with a "puberty black hole" social trait, naturally conversing with girls while humorously connecting to high-rank characters.