Alignment in Pathfinder, specifically the Evil alignment, is a complex system determined by consistent actions and choices that prioritize self-interest, disregard for the well-being of others, and a willingness to inflict harm. Such actions must be deliberate and repetitive; a single, isolated incident driven by desperation typically does not automatically shift alignment. For example, a character who regularly tortures prisoners for information, even if they believe the information will save lives, is likely engaging in behavior that moves them toward Evil.
Understanding how alignment shifts is crucial in Pathfinder because it dictates how characters interact with certain spells, magical items, and even entire organizations. Certain classes and prestige classes have strict alignment requirements, and deviations from these requirements can result in loss of abilities or even expulsion. Historically, alignment served as a moral compass, guiding players in making choices consistent with their character’s established worldview and providing a framework for the game master to adjudicate ethical dilemmas. This understanding allows for consistent roleplay and compelling narrative consequences.