Charlotte Arisaka Anderson, often called by her nickname Charl, is a seventeen-year-old girl of half-American, half-Japanese descent who plays a significant role in the story. She has long blonde hair, often styled with a braid, and emerald green eyes. Her typical outfit consists of a white dress top, a maroon skirt, short white socks, black dress shoes, and a turquoise brooch necklace. Born on October 10, she was raised by her parents, both of whom are in the military, under a strict and disciplined environment that included extensive combat training from a young age. This upbringing contributed to a somewhat solitary nature and a deep-seated sense of neglect, particularly in relation to her mother, Arisaka Kizue, and the death of her younger brother, Noa.

Charlotte’s personality is defined by her bravery, directness, and fierce loyalty. She is known for her explosive honesty, openly expressing both her positive feelings and her intense dislikes. Despite her formidable physical strength and combat training, she often struggles with complex intellectual challenges and strategic thinking, a weakness she herself acknowledges. Beneath her tough and often obstinate exterior lies a vulnerable side shaped by personal trauma and a strong desire to protect those she cares about.

Her primary motivation stems from her deep admiration for the detective Siesta. Charlotte was originally sent as an assassin to eliminate Siesta but was defeated. Following this loss, she came to idolize Siesta, affectionately calling her Ma'am and declaring herself Siesta's apprentice. After Siesta’s death, Charlotte is driven to protect her mentor’s legacy and works as an agent under Fūbi Kase, taking on dangerous combat, espionage, and protection missions.

Within the narrative, Charlotte initially appears as a rival to Kimihiko Kimizuka, resenting that Siesta chose him as her assistant. Their relationship is highly conflictual, marked by frequent clashes and her proclamations of hatred toward him. However, in critical moments, she demonstrates a reluctant but profound trust in him, acknowledging that if Siesta trusted him, she has no choice but to do the same. This dynamic evolves as they are forced to cooperate, leading to a complex bond that oscillates between rivalry and deep, unspoken complicity. Her relationship with Siesta is the most significant in her life, viewing her as a mentor and a maternal figure. Her connection with her own family is strained, characterized by feelings of abandonment stemming from her parents' focus on her ill-fated younger brother.

Throughout the story, Charlotte undergoes considerable development. She begins as a lone operative but gradually learns the value of teamwork, largely through her interactions with Kimihiko. In a pivotal moment, she is ordered to assassinate an ally, leading to a crisis of loyalty where she must decide between following orders and protecting her friends. Ultimately, she chooses to honor Siesta’s true legacy of protecting one’s companions. A significant part of her arc involves confronting her painful family past when she searches for her missing mother, forcing her to reconcile with years of neglect and grief over her brother’s death. Through these trials, she evolves from a solitary assassin driven by admiration into a dedicated agent who understands the importance of trust and collaboration.

Charlotte’s notable abilities are almost entirely physical and tactical. She is an exceptional fighter, considered the strongest in close-quarters combat among her peers. Her skills include expert marksmanship with pistols and sniper rifles, proficiency with knives, and mastery in driving cars, motorcycles, and even piloting a helicopter. While she lacks any supernatural powers, her rigorous training as a soldier and agent makes her a formidable ally in the field. However, her lack of strategic and deductive reasoning means she often relies on others, particularly Kimihiko, to solve complex puzzles and devise intricate plans.