Note: I treat “milk factory BL novel” as the specific subgenre/trope in boys’ love (BL) fiction where a male character — often young, vulnerable, or commodified — is depicted as a source of milk (literal lactation or metaphorical “milk”-production), and their body becomes central to erotic, emotional, and power dynamics. This analysis covers historical and cultural origins, recurring characters and plot structures, thematic readings (gender, consent, commodification), stylistic devices, audience function, ethical concerns, cross-cultural variations, and scholarly/reception contexts. I assume the reader is familiar with BL as a genre of romantic/erotic fiction focused on male–male relationships.