In the Amory Wars, the souls of the deceased are sent to power the Keywork. When a living man, Sirius, enters the Keywork, the souls attempt to possess him.
While Sirius is still in the keywork, two souls named Vic and Sentry fight with each other after first possessing Sirius.
My question, is there any evidence that any of the souls interacted before Sirius' arrival or did his arrival trigger the interaction between the souls?
Here's the wikipedia reference to the story I'm referring to - I have a feeling not many are going to be familiar with it.