Ritual of Rain

A mission only spell. It's required to perform a ritual on a certain structure, either an Epic structure, like a pillar or pylon, or a certain guard tower. At the particular tower or structure, one have to right click it, the option to perform the ritual will be there. Sometimes it requires a certain item to be active, the required item should be activated, and after right clicking the structure, again the option to perform the ritual will be there.