 When writing the script , Uchikoshi began by writing a basic story . One of the new additions to the story was the Ambidex Game , which was intended to have philosophical significance , as the logical decision made in it hurts the characters both on a group level and on a personal one . He then designed the characters he felt were necessary to the story . He aimed to create a balanced cast of supporting characters , in terms of genders , personalities , and ages represented . While designing the characters ' personalities , he used the Enneagram of Personality as a reference . It was important to him to create a mystery behind them , to make players curious about who the characters are and what their pasts were like . Another important element was the use of misdirection : By deliberately making certain characters seem like bad people , he would get players to focus on them more , making it more difficult for them to see who the " real bad guy " is . He decided to not give Sigma a strong personality , in order to make it easier for players to empathize with him . Because the Moon was one of the game 's major themes , the character Zero III appears as a rabbit - a reference to the moon rabbit in Japanese folklore . 
