Mahiru Shirota is portrayed as a slender adolescent boy with short, light brown hair that frames his face and large, expressive brown eyes, emphasizing his youthful and approachable appearance. His build reflects that of an ordinary high school student rather than a combatant, aligning with his characterization as someone who values simplicity and avoids unnecessary complications.

His most recognizable outfit consists of a brown shirt with a white collar, layered beneath an orange jacket with rolled-up sleeves, paired with beige pants that extend below the knees. He typically wears a red tie loosely around his neck and completes the look with white-and-orange sneakers. The predominance of orange in his clothing has become a visual identifier for the character, symbolizing warmth, optimism, and energy.

In artwork and promotional material, Mahiru is often associated with orange tones, but his wardrobe is not limited to this palette. He has been depicted in more formal attire, such as a vest and tie, when situations demand it, highlighting his flexibility despite his preference for comfort and practicality. A notable accessory is the black-and-white striped wristband gifted to him by Sakuya, which he occasionally wears and which serves as a subtle reminder of their bond.

Mahiru Shirota is characterized as open-minded, straightforward, and independent. He is unafraid to express his true thoughts and feelings, which at times makes him openly critical of others. His philosophy of valuing simplicity over unnecessary complication guides much of his behavior, and he often demonstrates a responsible outlook uncommon for his age. Mahiru is self-reliant, preferring to depend on his own abilities rather than seek help from others, a trait shaped by his belief that reliance is unnecessary unless absolutely required.

Although calm by nature, Mahiru is shown to have limited patience, raising his voice when irritated or frustrated. In group dynamics, he frequently assumes the role of a caretaker or “mother hen,” acting more maturely than his peers and guiding those around him. This quality reflects both his practical mindset and his instinct to protect and organize.

Mahiru is also noted for his ability to use words effectively, often encouraging others at critical moments. His straightforward honesty allows him to offer reassurance without overcomplicating matters, giving him a stabilizing influence within the Servamp conflict. Once committed to a decision, Mahiru shows strong determination and persistence, refusing to abandon his goals even in the face of significant obstacles.

Mahiru Shirota grew up with a philosophy inherited from his uncle, who raised him after the death of his parents. His uncle often emphasized that “simple is best,” a saying that shaped Mahiru’s worldview and encouraged him to value straightforward solutions over complicated ones. This outlook became central to his personality and later defined the way he handled conflicts involving the Servamps.

As a child, Mahiru lived a relatively ordinary life and avoided standing out among his peers. He developed a habit of taking on responsibilities quietly, relying on himself rather than others, and learning to handle daily challenges with independence. This background instilled in him a strong sense of self-sufficiency, which persisted into his high school years.

Mahiru’s life took a significant turn when he picked up a stray black cat, whom he later discovered to be Sleepy Ash, the Servamp of Sloth. This accidental encounter bound him to the world of vampires and contracts, thrusting him into a conflict between the Servamps and their Eves. Despite the danger, Mahiru continued to apply his belief in simplicity and responsibility, often acting as a mediator and stabilizing force within the group.

As the Eve of Sleepy Ash, Mahiru Shirota wields a Lead, an item that manifests in different forms depending on his bond with his Servamp. Over the course of the series, his Lead undergoes several transformations:

Broom
The first form of Mahiru’s Lead appears as a broom, which he can summon at will and utilize in various ways, including flight. By spinning together with the broom in a breakdancing motion, he can generate powerful whirlwinds capable of breaking through reinforced structures, such as a concrete ceiling. However, Mahiru initially struggles with controlling this form effectively.

Spear
After entering Kuro’s mind, Mahiru’s Lead evolves into a spear. This form provides greater offensive capability, allowing Mahiru to strike and slice enemies with precision. Unlike the broom, Mahiru demonstrates complete proficiency with the spear, using it confidently in combat situations.

Elpis
Introduced in the anime and later appearing in the manga, the Elpis form allows Mahiru to access the memories and emotions of his opponents. The Lead manifests as different keys depending on the individual being confronted, symbolizing the unlocking of hidden truths and inner struggles.

Akira Shirota
Akira was Mahiru’s mother, with whom he shared a close and loving relationship until her death. Her passing deeply affected Mahiru, causing him to withdraw from his friends and isolate himself emotionally. When Licht Jekylland Todoroki later revealed Mahiru’s memories, the strongest recollection that surfaced was of his happy times with his mother, highlighting the profound impact she had on him. These memories depict Akira as a caring and gentle parent, and Mahiru’s grief demonstrates the lasting significance of their bond.

Sleepy Ash (Kuro)
Mahiru initially found Kuro frustrating, often clashing with his indifference and avoidance of responsibility. Despite this, their relationship gradually deepened as Mahiru consistently expressed concern for Kuro’s well-being and sought to treat him as an equal partner. Mahiru respected Kuro’s desire for privacy, refusing to force him to reveal his past, while Kuro though outwardly dismissive showed loyalty by protecting Mahiru during battles. Their partnership solidified when Mahiru rejected offers from C3 to break his contract, declaring his trust in Kuro and his determination to decide their fate together. This mutual recognition eventually led Kuro to openly acknowledge Mahiru as his partner.

Sakuya Watanuki
Sakuya became Mahiru’s closest friend during high school, and the two often spent time together after classes. Although it was later revealed that their shared childhood memories had been fabricated due to Sakuya’s manipulation as Tsubaki’s subclass, Mahiru continued to view him as a true friend. Upon learning Sakuya’s real past and his conflicted feelings, Mahiru resolved to free him from Tsubaki’s control. This act of acceptance and loyalty strengthened their relationship, and Sakuya, once indifferent, came to genuinely value their friendship.

Misono Alicein
Mahiru’s first encounter with Misono was tense, as Misono attempted to take Kuro from him. However, upon understanding Misono’s motivations, Mahiru offered his friendship, which Misono though embarrassed accepted with gratitude. Their bond quickly grew, with Misono becoming protective of Mahiru and risking his life to save him from Tsubaki’s subclasses. Mahiru, in turn, showed concern for Misono’s fragile health and regarded him as one of his close friends, appreciating his true kindness beneath his outwardly grumpy demeanor.

Tetsu Sendagaya
Mahiru and Tetsu formed an easy friendship based on their similarly straightforward personalities. While Mahiru is sometimes baffled by Tetsu’s unusual behavior, particularly in promoting his family’s inn, he admires Tetsu’s strength and reliability. Tetsu, in turn, respects Mahiru and often refers to him as “Big Brother Mahiru,” demonstrating his trust and willingness to follow Mahiru’s guidance. Their mutual respect makes them dependable allies in the conflicts surrounding the Servamps.