Grevil is an aristocrat who had forced the local police to make him a detective purely because he had an interest in crime. The most noticeable thing in his appearance is his drill-like hairstyle that Kazuya thinks could be used as a deadly weapon. Despite being a terrible detective and always having to rely on Victorique to solve his crimes, he usually refuses to acknowledge that she even exists. When he comes to the library he speaks about the case that troubles him to Kazuya, saying that it helps him to clarify his thoughts. Kazuya tries to get him to tell it to Victorique, which he ignores. Victorique tells Kazuya to chat with the detective, that she will just read her books; if she says anything to herself, pay no attention. This is because he is Victorique's half brother and even if they are family they could never acknowledge each other in public. His mother was their father's proper wife and because he is the eldest son he takes all the glory for solving crimes and will take over after their father dies. He is described by Victorique as a heel and a playboy.