"Deals 2000 Damage Per Second to all enemy mercenaries and beast inside the area"
Acid Rain is similar to a catapult attack and works exactly the same as one. Only mercenaries and beast within it area will get damaged. Acid Rain has a 10 seconds duration and does a total of 20000 damage. This is very helpful to for killing mercenaries in Watch Posts or enemy beasts. Acid Rain can be produced in the Blacksmith
Acid Rain is an Event Item which can only be unlocked at the Event Store. You will need to gain Event Points in the Event to be able to unlock the Event Items.