Grévil de Blois is the eldest son of the powerful de Blois family, a prominent aristocratic household in the Kingdom of Sauville. As the heir to the family, he was raised under the strict expectations of his father, Marquis Albert de Blois, and is deeply bound by familial duty and social status.

In his youth, Grévil was a calm and soft-spoken young man, often seen with unkempt shoulder-length hair. During this time, he developed a close friendship with Jacqueline, a woman he continues to love and admire even after her marriage. Though his feelings remain unfulfilled, he continues to care for her deeply.

Grévil’s relationship with his younger half-sister, Victorique de Blois, is complicated. Although they share the same father, Victorique was born from an arranged union between the Marquis and a foreign woman, making her a source of political interest rather than familial affection. Due to this, Victorique was isolated from the rest of the family and society, confined to the academy’s library tower. Despite often acting cold or dismissive toward her, Grévil shows signs of protectiveness and inner conflict, occasionally challenging their father’s decisions regarding her treatment.

Grévil’s role as a police inspector came not from training or merit, but from influence and personal interest. Fascinated by mysteries and crime, he forced his way into a position within the Sauville police department, treating detective work as a nobleman’s pastime. Although he lacks the skills of a true investigator, he repeatedly solves high-profile cases by secretly relying on Victorique’s deductive abilities. He regularly visits her under the pretense of offering updates or asking casual questions, only to later take credit for her solutions in public.

While Grévil often appears self-centered or flamboyant, his behavior masks a more conflicted character, torn between his aristocratic obligations, personal desires, and the guilt he feels regarding his family’s treatment of Victorique.

Grévil de Blois is a tall, attractive man in his twenties, known primarily for his eccentric and elaborate drill-shaped hairstyle. The style is time-consuming to maintain, and he is rarely seen without it properly set. In contrast, during his earlier years, Grévil wore his shoulder-length hair loose and unkempt. According to Kazuya Kujō, Grévil’s hair appears silky, while Cecile Lafitte notes that it carries a floral fragrance a result of the scented shampoo he uses, as Grévil himself admits.

He typically dresses in a stylish white coat paired with slacks and a signature pink ascot. In the past, his attire featured a similar coat complemented by a blue ascot instead.

Grévil de Blois once exhibited a calm, soft-spoken, and mild-mannered personality in his younger years. However, in the present, he often displays a more eccentric and theatrical attitude, exaggerating his speech and behavior particularly around those familiar to him. Despite his often comical and flamboyant exterior, Grévil reveals a more serious and dutiful side when it comes to following the orders of his father, to whom he feels a strong sense of responsibility as the eldest son and heir of the de Blois family.

Grévil’s role as a detective is, in truth, more of an aristocratic indulgence than a professional calling. He coerced the local police force into appointing him as a detective purely due to his personal fascination with crime. In practice, however, he is an ineffective investigator. One of his most notable blunders involved nearly implicating Kazuya Kujō in the murder of a government official, a crime actually committed by the victim’s lover. This misstep could have sparked a diplomatic crisis between Sauville and Japan. Because of his limitations, Grévil frequently relies on the brilliant deductions of his half-sister, Victorique de Blois, to solve cases, often consulting her in secret.

His relationship with Victorique is complex and strained. Although he visits her regularly to seek her help, he remains emotionally distant and hesitant to engage with her directly, knowing she often demands unusual forms of repayment for her assistance, his elaborate hairstyle being one example. He occasionally speaks harshly to her, calling her heartless or incapable of love. Despite this, Grévil does care for Victorique, as shown by his objections to their father’s treatment of her and his concern for her well-being.

Grévil is also in love with his best friend, Jacqueline, despite her being married. He holds her in high regard and values her opinion deeply.

Victorique de Blois
Grévil shares a complicated and often strained relationship with his younger half-sister, Victorique. Although he frequently visits her under the guise of casual conversation, his true intent is often to consult her for help solving difficult cases. He rarely acknowledges her contributions publicly, taking credit for her deductions to maintain his reputation. Despite his cold and dismissive attitude, Grévil shows signs of genuine concern for Victorique’s well-being. He occasionally protests their father’s harsh treatment of her and demonstrates subtle protectiveness, revealing a conflicted sense of familial duty and affection.

Albert de Blois
As the eldest son and heir to Marquis Albert de Blois, Grévil feels a strong sense of obligation to his father. He obeys his orders without question, even when they conflict with his personal beliefs. His loyalty to the family name often puts him at odds with his own moral compass, particularly when it concerns the treatment of Victorique.

Jacqueline de Signore
Jacqueline is Grévil’s best friend and the object of his unrequited love. Though she is married, Grévil continues to care for her deeply and values her opinion above most others. His affection for her remains a quiet and constant presence throughout the series, adding a layer of emotional depth to his character.

Kazuya Kujō
Grévil initially treats Kazuya with suspicion, even going so far as to wrongfully accuse him in a murder case, an error that could have caused diplomatic conflict. Over time, however, Grévil comes to respect Kujō, particularly for his unwavering loyalty and support of Victorique. While he never fully sheds his condescension, their relationship evolves into one of reluctant mutual acknowledgment.