Lich.

Powerful human sorceresses who changed into undead. There are also those who chose to become liches of their own accord in pursuit of eternal life and limitless knowledge. They possess much greater magic than they did while amongst the living. They are terrifying high rank undead that can freely use various spells such as “necromancy” which reanimates corpses into undead servants, and “eromancy” which manipulates lust and heightens pleasure. Most of them have a strong fixation with and thirst for knowledge of sorcery, and pleasure, which they awakened after becoming monsters. Even in death, they continue their magical research and experiments to master sorcery and reach the depths of pleasure.




They usually immerse themselves in their research in dwellings away from human settlements, and they rarely reveal themselves in front of people. However, a human man is absolutely necessary to them as they replenish their magic power by taking in essence, a man’s body serves as a test subject, and there are spells and SUS experiments which require both a man and a woman to perform, so if they spot a man, they’ll aggressively attack in an attempt to subdue him.

I don't think I can show the entire thing here.
Story - Kenkou Kross