In December of EC 135, Sateriasis Venomania forged a contract with the Demon of Lust, gaining the power to brainwash women. After the New Year Festival the following year, the Duke brainwashed Lukana Octo during her return trip to Mystica. After failing to also brainwash a witness, Sateriasis had Lukana live in his mansion's basement in Lasaland as his concubine. Several days later, in February, Sateriasis tracked Mikulia Greeonio to Abito and successfully recruited the witness into his harem. Lukana then began tailoring new, revealing outfits for the harem to wear.
Afterward, Sateriasis enchanted and abducted Lolan Eve from Lisa-A and later Mirigan Adi from Evnemi. In March, he infiltrated the Glassred Mansion and brainwashed Carol Shields, using the maid to help him brainwash and abduct Gumina Glassred. He then added Hakua Netsuma, Queen Yufina Marlon, Sonika Sonic, Lazuli Blue, and Priema Soap to the harem. In April of EC 136, the Duke brainwashed Lilien Turner in Mystica before adding Mewtant Lusha, Tette Cetera, and Rio Neja to his harem.
The Duke then brainwashed Mickina Olliba and Neruneru Nerune, using the latter to lure out Princess Maylis Beelzenia and abduct her as well. At some point, Venomania added Yukina Kaina, Rindo Blum, and Josephine Francois to the harem. Sometime during the period, Lolan Eve died. Once Annlee Sweets was brainwashed and abducted, the old woman began monitoring the harem's health. At some point, Sateriasis impregnated Lukana, Mikulia, and Maylis.
In EC 137, Duke Venomania attempted to abduct Elluka Clockworker before being fatally stabbed by a disguised Karchess Crim. As the Duke died, his Lust spell was broken and the enslaved women quickly fled the mansion, leaving the harem and Sateriasis behind.
Following the Duke's assassination, many of the women returned to their original homes unharmed. However, due to their connection to him, many of the former harem members faced intense persecution by Levin believers thereafter. The Duke's progeny suffered similar persecution in the succeeding centuries. Rumors of the harem ranged from claiming it was as little as twenty women to as many as a hundred.
- The harem's head count is updated at the end of each numbered chapter in Deadly Sins of Evil: The Lunacy of Duke Venomania, ending with "0" in chapter 6.