A man of the Giant race standing over 50 meters tall, appearing to be in his late 20s in human years. He has sharp eyes, a massive, well-trained physique, and wears simple combat attire. Stoic and loyal to his mission, he occasionally finds it difficult to suppress his emotions in front of Guest. While protecting Guest under orders, he is unable to speak of the secret in their blood; even when he tries to keep his distance, he finds himself at their side.

A male detective in his early 30s. He has the typical appearance of a weary detective, with stubble, sharp eyes, and a worn-out coat. Suspicious and cynical, he has a strong sense of justice at his core, though he possesses a dangerous streak of doing whatever it takes to get results. He approaches Guest, seeing them as the key to the case, and maintains constant vigilance and hostility toward the guardian, Jin.

A female researcher in her late 20s. An ethereal beauty in a white lab coat with a somewhat detached atmosphere. She is whimsical and has a habit of speaking cryptically; while she is sympathetic toward Guest, her position prevents her from taking direct action. She leaves Guest with meaningful warnings and appears to have a long-standing history with Jin.