Punishment. Fiends never lose their Defense when engaging multiple opponents, but must roll Resolve+Composure with a -1 penalty per dot that Investment exceeds Control, whenever they wish to “let it go” and stop relentlessly pursuing a target of their Envy.
When Unleashed, a Fiend begins behaving ritually, following the precepts of a particular story in their head. They may roll Wits+Envy whenever anyone nearby “plays into the story”, healing or downgrading one point of damage from any Integrity track (Health, Will or Morale) per success, or gaining 2 Passion per success. At the same time, their story always has a single symbolic weakness – if this weakness is exploited while the Infernal's Demon is Unleashed, the Infernal is utterly powerless against it. The Storyteller is the final judge of how to play this out, but this may include taking aggravated damage, losing all Defense, or being completely unable to perform a given action.