How NOT to Summon a Demon Lord season 2 episode 5
Episode title: Black Dragon Clash
After rescuing Horn, Diablo learns of Horn’s secret. Meanwhile, Shera, Rem, and Lumachina make progress through the dungeon and reach the twelfth underground floor. When Rem opens the door, they find the man pursuing Lumachina — Gewalt. To make things worse, a Large Black Dragon appears with a terrifying blast of wind!
