虚実と鬼

In the context of the game produced by shizuka, "How do people become demons?" is not directly explained within the provided game description. The game itself is centered around a mystery set in a closed women's dormitory where "demons" are rumored to be hidden. Players interact with two girls who are possibly students at the dormitory, and the gameplay involves uncovering clues through conversations to determine which of the girls might be the "demon."

The narrative focuses on the protagonist, referred to as "I," who struggles to adapt to the situation. The game does not delve into the mechanics or lore behind the transformation into a demon, but rather uses the concept as a central mystery to drive the story forward.

For a detailed understanding of how people become demons within this game's universe, players would need to engage with the game's storyline and possibly uncover this information through the clues and interactions provided in the gameplay.