Whenever a character begins activating a skill with an overcast cost, the character's maximum energy is immediately reduced by the specified amount. This is represented as a grayed-out section on the right end of the energy bar, similar to how Deep Wound affects the health bar.
It is possible for overcast to reduce a character's maximum energy below 0: if the character had already overcast themselves to a maximum energy of 2, then cast a spell with an overcast cost of 10, they would then have a maximum energy of –8.
Overcast is recovered at a rate of 1 energy every 3 seconds. For example, it would take 15 seconds to fully recover from casting a spell with an overcast cost of 5. Like all status effects, overcast is also removed completely whenever you enter a new zone.
EliteSpell. Target foe suffers 10...42...50 lightning damage. If you have more Energy than target foe, that foe suffers 10...42...50 more lightning damage and is knocked down. This spell has 25% armor penetration.
EliteSpell. You Ride the Lightning to target. All adjacent foes are Blinded for 1...4...5 seconds. If your target is a foe, it is struck for 10...58...70 lightning damage. This spell has 25% armor penetration.
EliteSpell. Target foe and all adjacent foes take 15...51...60 fire damage. If you have more Energy than target foe, that foe and all adjacent foes take an additional 15...51...60 fire damage and are set on fire for 1...8...10 seconds.