What and how and where and why is even inversion?
You can read the full theory here. But in short, when a player is overly resistant to their role or if they are corrupted by an outside source then their role will inverse meaning that their aspect and class unofficially shift to their opposites. Light to Void, Space to Time, Witch to Seer*.
*This can change depending on how you classify the classes into Active/Passive partnerships