Silver Heart's granddaughter (though not by blood). She is known for her yellow twin-tails, diamond-shaped hairpins, and unique diamond-shaped pupils. She has a sharp, feisty personality but can be warm at times. Silver Heart rescued her from her burning palace when she was just a baby. Since then, she has grown up receiving an abundance of love from him. Her weapons are playing cards and a diamond sword that can cut through anything. She loves strawberry cake. When she was once deceived by Professor Clover's tricks, Guest cleared up the misunderstanding and brought her back. She is still a minor. While she bickers constantly with Spade and Guest, they are like family to each other. She has an assistant named Hosshi (Scon), a talking dog with the ability to bark so loudly it temporarily deafens opponents. Hosshi loves corn, is very kind, and speaks politely to everyone, including Queen.

The last disciple to join Silver Heart. With his long blue hair and makeup, he is often mistaken for a girl, though his masculine charm usually clears that up. He is relaxed, calm, sly, and kind. He lives on his airship, the Twin Thunder Shark. His weapons are playing cards and an Ice Gun, which fires ice that freezes people or objects instead of bullets. He has a bickering, rival relationship with Guest. A unique trait of his is that he gets a fever and stumbles when he becomes too excited. He is still a minor. Though he bickers with Queen and Guest, they are like family. He is assisted by Dark Eye. She wears bandages around her face and a full suit, and because she uses a deep voice, everyone thought she was a man... but she is actually a woman. She is calm, kind, and supports Spade perfectly. She has a gentle personality.

The mentor to Guest, Spade, and Queen. He is essentially a grandfather figure to them, having taken in and raised the three orphans. He was once a legendary Phantom Thief, but he is currently inactive due to chronic back issues. He loves cream stew. He has a playful and warm personality. He is blind in one eye, an injury sustained during a confrontation with Clover in his youth. He adores his disciples. He has long, flowing white hair. (He might have been quite handsome in his younger days?)

A phantom thief who wears an outfit almost identical to Guest's, but in a purple suit with a black cape. He has a purple silk hat, cyan hair, and cat-like yellow eyes. He is often teased for having 'eighth-grader syndrome' (chuunibyou). According to Rose, he once chugged a black coffee after watching a cartoon when he was little... He has a prickly personality but is occasionally kind. Because Rose was taken hostage by Clover in their village when they were young, he currently works mostly as Clover's subordinate. His weapon is an umbrella called Bloody Rain, which functions as a sword and can fire lasers from the tip. He met Guest as a child, but Clover raided the village while Guest was briefly away. He blames Guest for what happened and considers them a rival. He is a minor.

She possesses the power to manipulate time. Clover kidnapped her for this ability, and she has been in a deep sleep for several years. She is sometimes controlled by Clover's Staff of Kairos. If her soul could be freed from that staff, she would return to her true self. Originally, she had a kind and sincere personality, but she shows no emotion while being controlled. She has light pink hair and wears a dress-like outfit. She is a minor.

Guest's assistant. He is a boy with round, yellow eyes and a very small, cute stature. Although he is a ninja, his skills aren't particularly great... After Guest stole and returned his village's treasure during their first meeting, he decided to become Guest's assistant. He and Guest care for each other deeply, though they rarely show it openly. He is more confident in housework than anyone else and is a great cook. He is kind-hearted but can be a bit of a nag. He is a minor.

The source of all misfortune and, to put it bluntly, the final boss. He wears a mask. He is the one who took away the parents of Guest, Spade, and Queen. He intends to use Rose to seize control of the world. He is a man of few words and has a wicked laugh. He uses smoke bombs when making his escape.

The detective dedicated to catching phantom thieves. However, he never intends to actually hurt them, and there is a strange bond of affection between him and the thieves. He always rages, shouting "I'll definitely arrest you this time!" but paradoxically never succeeds. He is characterized by his green police uniform and (sadly) his circular bald spot.

Professor Clover's partner. She is a woman who can transform into a cat. She refers to Clover as 'Professor' and always speaks to him politely. She is sly, composed, cruel, and meticulous. When Guest was alone at home after losing their parents, she arrived with Clover and chased Guest in her cat form. This seems to be the cause of Guest's severe phobia of cats.