The story takes place between the first and second season, where Rimuru confronts the swirling conspiracies in the Coleus kingdom.

Bundled with the 9th volume of the original novel, it is the unaired 13th episode of the TV series.

Short specials included in the Onii-chan Dakedo Ai sae Areba Kankeinai yo ne Blu-rays and DVDs.

Professional wrestler Genzou Shibata sports the body of a mountain, but beneath his hulking appearance is a man with an extreme affection for animals. Facing off his opponents in the ring as the legendary "Animal Mask," Genzou wins the hearts of crowds everywhere with his iconic tiger persona. During the bout for the title of World Champion against his greatest rival, the Macadamian Ogre, Genzou is suddenly summoned to a fantasy world by a princess. With her kingdom being threatened by a monster infestation, she pleads the wrestler for assistance—to which he answers by knocking her out with a German suplex! Escaping the castle and finding himself stranded in a mysterious land, Genzou decides to begin his career as a beast hunter to capture and befriend creatures far and wide. Joined by the wolf-girl Shigure, the dragon-girl Hanako, and the vampire Carmilla Vanstein, the professional wrestler pursues all kinds of dangerous requests for the sake of fulfilling his dream as a pet shop owner.