In the Realms of the Unreal (2004) on Netflix

Plot summary

For decades Henry Darger held menial jobs around Chicago, on his own and in poverty, without close family or friends. His off hours went into a 15,145-page illustrated fantasy manuscript about the Vivian Girls and a war caused by a child slave rebellion, full of religious imagery and heroic drama. He also kept journals and wrote an autobiography. His work came to light when he was moved to a hospital near the end of his life. The documentary mixes interviews with his neighbors and other acquaintances with narration of his writing and his illustrations.