In Caves of Qud, True Kin avoided mutation by staying in these self-supporting arcologies for thousands of years. If the player is a True Man, you can choose the arcology you originate from, and your caste. Each arcology has four playable castes to choose from.
Arcologies are self-contained, self sustaining cities that have systems for food production, sewage and waste disposal, and energy generation. Theoretically, a person would never need to leave an arcology, they could exist comfortably inside one.
The 3 Arcologies are as follows