Mito Juujo is a member of Guren Ichinose's squad and a colonel in the Japanese Imperial Demon Army. She comes from the prestigious Juujo family, one of the three prodigious clans that serve the Hiragi family. Mito is a minor character in the series, appearing in both the light novel and manga timelines. In the light novels she is depicted as a high school student, while in the manga she serves as a soldier. Due to her family's status, Mito was not treated like an ordinary girl during her upbringing. This changed when she met Guren, who would frequently frustrate her with snide comments and jokes, yet his refreshing attitude led her to develop an unrequited crush on him. She follows Guren despite his lower rank, showing her loyalty.

Mito has long, wavy crimson hair that reaches nearly to the back of her knees, usually tied in a ponytail with a purple hair tie, and purple eyes. She wears the standard Japanese Imperial Demon Army uniform but opts for trousers instead of the skirt, reflecting her practical and disciplined nature. In battle, Mito is dedicated and serious, prioritizing the safety of her team and the success of the mission. She is quick to act and can make tactical decisions, such as stepping on Shinoa's scythe to prevent her from engaging in a fight during a practice match. Despite her composed demeanor, she can be flustered by unexpected personal remarks, such as when Goshi mentions that Guren wanted to see her in a bikini. Mito is highly obedient to her superiors and remains resolute even when her teammates act impulsively, ensuring the mission's objectives are met.

Mito wields a cursed gear named Kagutsuchi that enhances her physical strength, allowing her to deliver powerful blows with her fists in close-quarters combat. She also uses spellcast techniques passed down through the Juujo family, placing a curse upon herself to boost her physical abilities. Her fighting style emphasizes speed, precision, and raw power, making her effective against vampires. As a colonel, she demonstrates leadership qualities that contribute to her team's effectiveness.

Mito participates in several key events, including the defense of Shinjuku from a large-scale vampire invasion, a practice match against Shinoa Hiragi's squad at the Ebina rest stop, and the mission to target vampire nobles in Nagoya alongside one hundred Moon Demon Company soldiers. Her relationships with her squad members reflect deep loyalty and trust. She holds Guren in high regard as her squad leader and seeks guidance from Shinya when Guren is captured. She interacts with Shinoa's squad during training, assessing their skills and encouraging growth. A significant hidden aspect of her background is that she was killed by Mahiru Hiragi eight years before the main story and later resurrected by the Seraph of the End, a fact Mito herself is unaware of. This tragic past underscores her role as one of the characters affected by the larger conspiracy. While her screen time is limited, her contributions in battles and her unwavering dedication solidify her as a memorable and respected member of Guren's team.