Dear Santa is a young boy of approximately ten years old who serves as a Janitor, a specialized cleaner, and is a member of the team known as Child. He holds the classification of a Giver, a human tool user who can channel their power into a specific object to use as a weapon.

Physically, Dear Santa is notably short, standing at 130 centimeters tall. He has a very distinctive appearance, featuring a head of hair that is bicolored, with the right side being brown and the left side white, which is styled and tied into several clumps. His face is marked by visible freckles across his cheeks, and he has blue eyes. His typical attire consists of oversized, baggy clothes that seem to be chosen to allow for future growth, which accentuates his small stature. The most constant element of his design is a pacifier he keeps in his mouth, which is not just an ordinary object but his primary tool in combat.

Personality-wise, Dear Santa is a character of few words, as he is never shown speaking and instead communicates almost entirely through facial expressions, gestures, and small noises. He has a perpetually furrowed brow that gives him an air of being constantly annoyed, irritable, or intimidating. Despite this gruff exterior, he possesses a clever and somewhat impudent streak. This is particularly evident when his desire for sweets is involved; for example, he has been observed staring intently at the protagonist Rudo Surebrec while he was eating candy until Rudo relented and shared. Upon obtaining the treat, Dear Santa displayed a small, satisfied smile that suggested his longing look was a calculated act. He has a deep fondness for sweets and sleeping, and he detests boring moments and long-winded conversations. A notable weakness is that he becomes very drowsy at night, which can be a hindrance during extended missions. Despite his dismissive and irritable demeanor, he has shown no hesitation in expressing worry or concern when facing a dangerous adversary, revealing a hidden depth of care for his comrades.

Within the story, Dear Santa operates as a full member of the Cleaners, taking on dangerous assignments as part of Team Child. His most significant relationship is with his team leader, Bro Santa. Although they are not related by blood, their bond is consistently described as that of a genuine father and son. Bro Santa acts as his protector and parental figure, and Dear Santa in turn shows him trust and affection, suggesting a softer side beneath his perpetually irritated expression. He also exhibits a quiet curiosity about the protagonist Rudo Surebrec, though at times this curiosity seems opportunistic, particularly when there is a chance to obtain food. He has shown visible irritation when another character suggested he had taken an interest in Rudo, almost to the point of anger. He also dislikes being called nicknames, particularly those that emphasize his small size.

Dear Santa's notable abilities are derived from his role as a Giver. His chosen Vital Instrument, or human tool, is his pacifier, which is named Centralian. In combat, this object serves as a powerful weapon. The pacifier is described as having an amplifying effect, where it may grow stronger or enhance its user's power based on the amount of damage he deals to opponents. This allows him to fight effectively as a frontline combatant, described as a "bruiser" who punches hard, despite his young age and small size. His fighting style, combined with his youthful appearance and choice of weapon, creates a striking contrast that makes him a memorable and effective member of the Cleaners.