The Book of the War
Kaiwar (also spelled Kaiwur) was the site of one of the Thousand-Year Battles of the War in Heaven. Like Mohandassa, it may have been only a side-effect of Utterlost.
It was the only one of the Thousand-Year Battle sites that was still accessible. Devonire met the Immaculata Formosii there in an attempt to obtain the Grandfather’s Arm. (The Book of the War)