Black cloud of vengeance

A black cloud of vengeance was a monstrous sentient storm found in Zakhara.

Creation
Though their true origins and nature were unknown, there was much speculation about black clouds of vengeance. Some thought they were the creations of those who violated the Laws of the Loregiver, or that they were the instruments of the Loregiver, sent to punish breakers of the Law. Others declared they were sent by Fate itself to punish those who dared break her laws. Some claimed they were the products of potent magicks that had once been unleashed. All this was said to have occurred in the early days of the world, before the Loregiver's beneficence was known. It was said their occurrences were remembered in even the earliest memories of elven grandfathers by 1367 DR. Despite being incredibly rare, they were known to all cultures in Zakhara, as a sign of their awesomely destructive power.

Although many people believed that only one black cloud of vengeance existed, sages held that there were actually several of them. However, only one would be observed at a time.

Description
Black clouds of vengeance took the form of enormously powerful monsoons or thunderclouds. Some were large enough to engulf whole cities. Bright red lightning flashing occasionally within their dark depths. Black clouds combined the elements of fire and air into a deadly combination.

Their coming was presaged by great winds that blew hot, hard, and fast. They echoed with thunder and carried sand mingled with ash and soot, which darkened the air and ground before them. The sand was picked up the black cloud's winds in its previous courses across the land. The winds increased their fury and roar as the cloud approached. Their violence could only be compared with the strongest desert storms.

They were capable of moving against even the strongest gales if they wished, which indicated their sentience. If a black cloud approached, one could only hope that it would veer away.

Combat
When it descended upon its target or was challenged by some would-be hero, the black cloud unleashed its full force, producing howling winds capable of destroying whole buildings. It also rained fire, and the resulting flames were whipped up and spread by the winds, burning the wreckage and people trapped inside the storm.

Ecology
Their diet was unknown, but black clouds seemed to thrive on inflicting devastation.

Society
Despite being known to be sentient, almost nothing was known of the habits of the black clouds of vengeance. It could not even be said for sure if they were alive.

They usually assailed cities or large camps in the desert. They never assaulted cities holding mosques of the enlightened deities or cities where genies resided. In fact, they had some way of knowing if a city held neither genie nor enlightened god. Nevertheless, it wasn't clear if they served the enlightened deities, or if they just feared the powers of the gods and genies. If not tools of divine retribution, it was speculated they might be free spirits, going wherever their whims led them. Regardless of the truth, they certainly encouraged piety and enlightened faith in Zakhara.