Butt Detective Characteristics: Male. Birthday November 4th. Age unknown. IQ 1104. Family: Father - Dandy. Mother. True to his name, his face is shaped like a butt. He is a classic detective who finds clues in complex situations, reasons through them, and catches criminals. He loves sweet potato pie and black tea. As a polite character, he is gentlemanly toward women and extremely courteous toward men. His weapon is a powerful fart attack fired from his mouth; those hit by this toxic gas show comical facial expressions and faint in agony. He cherishes his assistant Brown and other characters. His weakness is that he cannot eat spicy food. His unique butt-shaped head is not due to fat on his jaw, but his skull. The skull itself is butt-shaped. Ten years ago, he had a friend and partner named Daffodil. However, Daffodil vanished without a trace, and ten years have passed, but he solves a case after receiving a request letter from her.

Brown. Assistant to Butt Detective. A graduate of the police academy. He was originally an ordinary four-legged dog, but later, starting from the Mystery Genius Butt Detective series, he became the anthropomorphic beastman he is today. Interestingly, the puppies in the town where Butt Detective lives are four-legged dogs when young, but at a certain age, they enter a canine school for police dog training. After some time, they take bipedal walking classes, learn to speak, and become beastmen like he is now.

Phantom Thief U. A famous phantom thief who causes a stir in the world and the eternal rival of Butt Detective. He loves beautiful and clean things and wears a poop-shaped mask. As expected of a phantom thief, he is a master of hiding, escaping, and disguise. He is also very intelligent, rivaling Butt Detective in figuring out tricks. He mainly steals beautiful treasures from all over the world. He loves roses and has blue eyes; since he couldn't change his eye color when disguising, he was caught by Butt Detective and now covers his eyes when in disguise. Even so, he has flaws and keeps getting caught. He occasionally speaks French words like 'Très bien' or 'Adieu.' Following the cliché, even though he steals, he shows good manners in other areas.

Phantom Thief B (Berry). A very beautiful girl. She is evaluated as the best character among the phantom thieves because she is the only one who was not affected by Butt Detective's fart attack, living up to her reputation as a lucky thief. A beautiful villain.

Shopkeeper. (Real name: Taepung) The owner of the Lucky Cat Cafe, which is Butt Detective's regular haunt. A lucky cat beastman. It seems he was quite famous for boxing in his younger days.

The daughter of the Lucky Cat Cafe owner. She is a biracial child born between a lucky cat father and a cat mother, but seeing how much she resembles her father, it seems she took after his genes. She has a very active, brave, and strongly righteous personality. She is said to have learned martial arts and also has a kind side, such as carrying an elderly lady on her back across a pedestrian bridge. As the daughter of a cafe owner, she has made pancakes and lassi. She has also participated in a boxing tournament.

The police chief of the town where Butt Detective lives. Male. He is a Maltese. He trusts Butt Detective immensely and frequently asks for help. He loves round objects so much that he loses his mind and gets busy chasing them whenever he sees one. It's almost instinctive, and because of that, he sometimes makes matters more complicated.

Dandy for short. Butt Detective's father. A famous explorer and a team leader in the artifact management department of a museum. He is also an archaeologist and works to protect ruins from bandits. Like his son (Butt Detective), he emits farts from his mouth.