Alignment functions differently than a standard Pathfinder game. The 8 alignments that previously surrounded Neutral are still present. All references to 'Neutral' are removed. Neutral Good is now simply good, and Lawful Neutral just Lawful. Same with Evil and Chaotic. Additionally, there is the status of Unaligned. Mortal races, animals, and even most monsters are Unaligned. An alignment is a magical association with the power of good, evil, law, or chaos. It is not used as a tool to inform a character's personality or motivations. Some beings, such as outsiders, deities, and magical races are permanently aligned. A Lawful Good archon from the Bestiary still has the properties of both Lawful and Good at all times in this setting. Characters can become temporarily aligned through the use of class features, spells, or magical items. An Unaligned character who grabs a cursed item may become Evil aligned while it is in their possession even if they do not have a malicious personality and spells such as Protection from Evil and Detect Evil would affect them. A paladin who uses Smite Evil might be Good aligned for a few rounds while a cleric who casts the Holy Aura spell would glow Good for many days.
This shift in alignment is purely mechanical and would not force a change in attitude or personality right away. For most mortals use of aligned magic would cause a shift in character over time. If a warrior used a cursed sword that aligned the user Evil she could use it for months to protect the innocent people of her hometown but over time she would become more callous, selfish, and violent. The players are not forced to do this and could easily play a character that uses a power traditionally aligned against them. A necromancer who raises the dead as tools to help society rather than destroy it is as valid as a cleric who channels positive energy to heal his gang of bloodthirsty raiders. Whether or not an archon or demon would agree with these uses of holy/unholy energy is a different matter.