S1·E3 The Magic Castle of Spirits

Light, Lena, and Ayla are hired by the guild to figure out why some adventurers went missing and find them. When they arrive at the count's manor that is their one lead, they encounter adventurers who have been turned into undead. The three of them fight as they head deeper into the manor, where they find Dratena, who uses the "Necromancy" skill, waiting for them.