Ratatoskr (ラタトスク, Ratatosuku) is an organization created for the purpose of saving Spirits, the cause of spacequakes, through peaceful mean without killing the Spirits. As stated by Kotori, "The organization called <Ratatoskr> was an organization created for Shido's sake."
The organization known as <Ratatoskr> is only known (probably) by the upper level of the government and high-ranking military officials. The <Ratatoskr> Command center is on the airship <Fraxinus>, while their headquarters is located elsewhere (its location is still unstated).