Tensei shitara Slime Datta Ken OVA

Life in Tempest takes a few smaller, much messier turns away from its grand battles. When Shuna and Shion quarrel over Rimuru's squishy body, his attempt to make a slime-shaped cushion sends him searching for special materials and into a picnic that becomes far less peaceful than planned. Later, a simple idea to give Tempest more recreation produces its first sumo tournament, where friendly competition quickly becomes something nobody wants to lose.

The focus then shifts to Rimuru's days as a teacher at Freedom Academy. His students join an outdoor training exercise meant to prove how far they have come, but a journey that should be supervised practice turns dangerous when thieves attack. Suddenly, the children must rely on the skills they have been learning instead of merely demonstrating them.