Aku no Taizai: Venomania-kou no Kyouki  

The Lunacy of Duke Venomania, The Madness of Duke Venomania, Nanatsu no Taizai Series, 悪ノ大罪 ヴェノマニア公の狂気

Duke Sateriasis Venomania, in his youth, faced ridicule and derision from those around him. In later years, he struck a pact with the devil to gain an alluring charm towards females. Consequently, numerous women were drawn to his mansion's basement, where they formed a harem for him. Among these women was Gumina Glassred, his childhood companion who ultimately exposed his folly. Now, she is a young woman.