Takumi felt that the best way to write a mystery with a good climax is to reveal various clues, and then pull them together into one conclusion, and not have multiple possible endings. He said that the biggest challenge with that was to make the gameplay and story work together; the goal was to make the player feel like they have driven the story forward themselves, with their own choices, even though the game is linear. He only spent little time on writing a backstory for Phoenix before writing the first game's story, and instead made up dialogue and developed Phoenix's personality as he went along. He came up with the partner character Maya because he thought it would be more fun for players to have another character with them, giving them advice, than investigating on their own.