This is a biblical fantasy, set between the Fall and the Flood. The authors have created a very intricate world. The various locations in Heaven were described well and the descriptions of the angels were interesting. However, a few issues let the book down.
The prologue is a history/geography lesson. Some love this style but many people don't.
Because the authors wrote the story in a linear manner, the first eight chapters (following the flight of some angels from Heaven) form what is really a second long prologue. The actual story only really gets going after this.
There are a lot of characters (many just names), and a lot of hopping briefly into unnecessary heads. Sometimes, key scenes were followed from secondary viewpoints when one or more of the main characters were present/in the vicinity. Several of the main characters have more than one name. One had three.
Midway through the book, the schmeerps breed like rabbits. Many of the many coined terms have to be worked out based on (sparse) context. The characters wonder about the term 'porter' but are unfazed by the plethora of other words they come across. The words for time (danna, uturra, mina, etc.) were particularly confusing.
This story has great potential. With more editing and focus, it could be an amazing book.