This spiritual being was originally bound by the Uktena, Wendigo, and Croatan when they first came to the Americas, but the death of the Croatan and arrival of the European Garou allowed it to break free of its bindings.
At some point, the Storm Eater merged with a huge Weaver-spirit, making it twice as dangerous. It commands the powers of both the Weaver and the Wyrm. It primarily manifests as a huge Umbral storm, tearing apart everything in its path.
The Storm Eater is eventually rebound on December 28th, 1890 with the Rite of Still Skies. This requires 13 rank 6 Garou, one from each tribe save the Bunyip, to sacrifice themselves at 13 different caerns in order to bind the Bane. 
In the modern era, the Storm Eater's bindings began to falter again. Garou gathered in Las Vegas, Nevada, sensing that something was horribly wrong. When Anthelios, the Eye of the Wyrm, opened in the Umbra, it largely negated the Rite of Still Skies, allowing the Storm Eater to spin off powerful jagglings bent on devouring Wyld energies.
Rage: Tribal War centers its storyline around the Storm Eater possibly breaking free. They held a global storyline event in 2001 to see if the Storm Eater actually broke loose. Disaster was narrowly averted. The Children of Gaia thwarted the secret victory condition that would have given the Garou total victory, which was reflected in the storyline.