Mitsuru Tokieda operates as an A-Rank agent in Border's Arashiyama Squad, fulfilling the role of a middle-range All-Rounder. He sports medium-length dark blonde hair in a bowl cut and olive green eyes, typically seen in the standard Border uniform. Activating his trion body reveals black leggings and a red, high-collared athletic jacket adorned with the A-rank emblem patch on the right shoulder, featuring long black stripes down the center of each sleeve.

Tokieda exhibits a notably calm and levelheaded personality, setting him apart within the energetic Arashiyama Squad. He consistently maintains a neutral expression and seldom shows overt excitement. Possessing sharp observational skills regarding others, he speaks only when necessary or to relay vital information. This measured composure translates directly into swift combat reactions, enabling him to shield Arashiyama from an attack targeting his blind spot or intercept unavoidable bullets aimed at Kitora, even at the cost of taking the hit himself.

His supportive fighting style aligns with the meaning of his given name "Mitsuru" (充), translating to "fill/to be full, supply." His surname "Tokieda" (時枝) combines the characters for "time" (時) and "branch/limb" (枝).

Additional personal details confirm he is 16 years old, born on April 12th under the Aries zodiac sign, with blood type A. His preferences include rice cakes, oranges, and cats.