The Moon Phase system is first explained by Biggs and Wedge at the beginning of Ceodore's tales in The After Years as a mysterious side effect of the phases of the moon. During each phase, one particular type of battle command will have its effectiveness lowered, indicated by red lettering, while another is raised, indicated by green lettering. This condition not only applies to playable characters, but to enemies as well, and can be used to directly affect the difficulty of some battles with proper planning.