The Weathermaker is a feldspar block entombing the demon lord Onaikai. In the Demon Spawn War, a primordial lord named Talos ignored the order to execute him. Instead, Talos put him in temporal stasis, then put him a block of feldspar. Talos then devised a way to harness his energy, using it to power the magical properties of the block surrounding him. When Talos left Bal-Kriav, the location of this block was revealed to a few storm giant shamans. Talos told them, that the block was an altar and that through it they could control the weather. Some have attributed the rise of Aslauthroa to be a product of this artifact. They say it gave the giants the ability to increase crop yields or bring famine and ruin upon their enemies.
Today, a select few of Griddrir's storm giant shamans are allowed near Ottaki. Inside this temple to Talos is the Weathermaker. Those who are allowed to go here are said to be blessed by the lighting father, gaining the powers to control weather. They use it to bring rain, winds, and make the skies cloudy or clear.
In the Cinazan Front, the giants used the Weathermaker to summon a great cloud that pursued the Pillar of Horns. Negral, one of this ship's crew members, called this cloud the Weathermaker's Embrace, and the battle fought with in, the Battle of the Weathermaker's Embrace.
Use of the Weathermaker is not without side effects. Heavy use of the device's weather magic turned Esto'khar into a rain forest and Arnskar into a desert. The permanent changes to these areas came about in the Horgon Era when Aslauthroa used the device to help to build their empire.