Ryouichirou Monokaki, age 32....... Eldest son of the Monokaki Family. Genius social school locked room mystery novelist.
Kyoujirou Monokaki, age 31...... Second son of the Monokaki Family. Genius hard-boiled locked room mystery novelist.
Isaburou Monokaki, age 29...... Third son of the Monokaki Family. Genius medical locked room mystery novelist. Doctor at a clinic in Yatsuwako Village.
Tabishirou Monokaki, age 26...... Fourth son of the Monokaki Family. Genius travel locked room mystery novelist.
Camembert Monokaki, age 16...... Fifth son of the Monokaki Family. Not a genius, just a pretty face.
Fuika Monokaki, age 24...... Eldest daughter of the Monokaki Family. Genius sci-fi locked room mystery novelist.
Funika Monokaki, age 24...... Second daughter of the Monokaki Family. Genius YA locked room mystery novelist.
Fumika Monokaki, age 24...... Third daughter of the Monokaki Family. Genius historical locked room mystery novelist.
Mei Monokaki, age 21....... Fourth daughter of the Monokaki Family. Adequate Gothic locked room mystery novelist.
Fuichirou Monokaki, age 58...... Former head of the Monokaki Family. Greatest locked room mystery novelist in Japan.
Zerohiko Monokaki, age 80...... Fuichirou's father. Multimillionaire and all-purpose genius.
Teika Ojou, age 25...... Young Empress of Japanese Mystery.
Tsuyoshi Chusaita, age 57...... Police officer of Yatsuwako Village.
Manami Okamibara, age 32...... Proprietress of an inn in Yatsuwako Village.
Yoshinori Murawaka, age 24...... Young man from the village. Recently debuted locked room mystery novelist.
Saboten Iyokawa, age 26...... Locked room agent known as the “Locked Room Sage”.
Kasumi Kuzushiro, age 18...... Third year high school student.
Yozuki Asahina, age 21...... Third year university student.
Shitsuri Mitsumura, age 18...... Third year high school student.
All names are presented in Western naming order, given name followed by family name.