The episode bundled with the 13th volume is about the Sumo competition that held at Tempest for the first time, suggested by Rimuru. The three-part OVA bundled with the 14th, 15th, and 16th manga volumes is an original trilogy written by Fuse. Rimuru has been teaching Shizue's students at Ingracia Kingdom's Freedom Academy. The time has come for the school's annual outdoor training event, where the students will test their combat skills in the field. Rimuru is determined to win the competition and take home the prize money, but he is challenged by Jeff, an honorary teacher who sees Rimuru as a rival. The competition is underway when suddenly an unexpected enemy appears!

Set in the land of Yuguto, the people thought that the land they live is the size of the world, but it's actually divided into several areas, each with a respective king. Even though there were small wars among areas, the kings had roundtable meetings to maintain peace and balance. It was until a dark group of dark monsters appeared... (Source: MAL News)

Takumi Fujiwara is a skilled street racer, but he suffers a crushing loss against the team Emperor's leader Kyoichi Sudou due to his AE86 experiencing an engine failure. Doubting his abilities, the recent high school graduate is then approached by the Akagi RedSuns' team leader Ryousuke Takahashi, who proposes the formation of a professional street racing team. Although it would be the ideal way to improve as a street racer, Takumi remains undecided. Does the young street racer have what it takes to become a professional? Perhaps Ryousuke and the RedSuns can help him reevaluate his own doubts and misconceptions concerning street racing. However, first and foremost, Takumi decides to settle the score with Kyoichi Sudou... [Written by MAL Rewrite]

Second season of Rikei ga Koi ni Ochita no de Shoumei shitemita.