An intelligence training academy for developing spies. Foreign prisoners serve as instructors, training students to infiltrate other countries. In some cases, the students themselves are foreigners who have been kidnapped and brainwashed. In its original usage, "charm school" referred to a school for young brides.
EVA, a descendent of one of the Philosophers, graduated from a Philosopher charm school that taught anti-US spying techniques. She was trained as a potential sleeper agent. Before the war, The Boss had worked as an instructor at the school.