Tensei Kizoku no Isekai Boukenroku: Jichou wo Shiranai Kamigami no Shito season 1 episode 11
Episode title: Omen of an Onslaught
Cain finally gets to participate in a magic class, this time to learn summon magic... and he ends up summoning the Prince of Darkness. Meanwhile, signs of a monster onslaught have been observed in the Forest of Monsters.
