Training is the primary gameplay mechanic where you "teach" the corrupted women to explore their darker desires. The training interface allows you to choose different actions, and as their experience grows, new options unlock.
Lavinia is the Demon King's wife, sent to monitor your progress. She can become a dangerous ally or a romantic complication depending on your choices, adding a layer of complexity to your mission as you navigate not just the Hero's party, but also your own superiors. Hero Party Must Fall Guide