Pairing: Barnaby x Kotetsu Doctor Saito runs some experiments on Kotetsu and presents the end results to Barnaby as a birthday present.
Chika Suzugamori and her traveling companions solve mysteries and go on day trips!
A special partially-color booklet released by Kodansha on March 9, 2020 bundled with a special edition of Volume 7.
Pairing: Barnaby x Kotetsu Contains 2 stories: 1) Boku no Yome - by Kureten Barnaby and Kotetsu have finally gotten married and are living the newlywed life when Kaede comes to visit. 2) Ore no Yome - by Kamikaze Gin Barnaby has taken a break from work to be a housewife after marrying Kotetsu, but he can't help worrying about Kotetsu while he's not around.
Pairing: Barnaby x Kotetsu Kotetsu has always simply gone along with what Barnaby wanted, and as a result he doesn't realize his feelings for Bunny until it's nearly too late.
A stand-alone story of Boon getting bullied. Is set in a different universe from "Tsunbaka" but has the same main character.
Amaretto, a human girl who had lost her family and was on the verge of breathing her last alone in the slums, is rescued from her plight by a suspicious man in a black suit. The man, who introduces himself as Ginjo, claims that Amaretto has the talent to be an "Idol," but... Alongside Redheart the Ogre and Karimo the Fairy, she begins her journey as an idol. What does the future hold for her?! The story of a rising star in another world begins!!
A self-help book.