Gaiden 2: [The Altar of Darkness] "I’ll make sure a virgin sacrifice is ready. Time to summon a demon." Walpurgis, 12 years ago... The origin of a legendary, smash-hit anime—concluded here!! Three members of a magic circle—led by Hiroko Takagi—harness the terrifying power of a grimoire to unleash a series of lewd, magical spells throughout the academy. Nami Kozono, one of the "victims," ​​decides to join the magic circle to exact her revenge. Meanwhile, realizing that her feelings for Reika Kitami will never be reciprocated, Nami sets a sinister scheme into motion... The truth behind Walpurgis is unveiled, layer by layer. The secret of Walpurgis from 12 years ago—the origin of a legendary, smash-hit anime—is finally brought to light!!