Plot Summary:Rimuru suddenly realizes that there's nothing to do for recreation in Tempest. He suggests sumo wrestling as a way for everyone to have fun together, and his friends are immediately on board with the idea.
OAD《外传:M的悲剧?》和《外传:HEY!尻!》分别收录于漫画12卷、13卷特装版
7月 泳装篇OAD
12月 相扑篇OAD
OAD1 コミックス第12巻限定版収録。
OAD2 コミックス第13巻限定版収録。