Descent of Angels is the sixth book in the Warhammer 40K Horus Heresy Series. The problem is it leaves out much of the 40K part and doesn't even mention the Horus Heresy. If it wasn't for the fact that this book is the first part of a Mini Dark Angels series, I would skip it and move onto Legion.
Written by Mitchel Scanlon, Descent of Angels is grouped with the rest of the Warhammer 40K Horus Heresy series, but it really doesn't belong with them....well not yet anyway. The story focuses primarily on the history of the Dark Angels Space Marines. Most of the events of the story take place on the planet Caliban prior to the arrival of the Human Imperium. Several major characters, such as the Lion El'Johnson and Luther are introduced, but not many of the events prior to the arrival of the Imperium have little impact on post-Imperium Caliban.
To be honest, this book was probably the least entertaining one in the series so far. I read the first five Horus Heresy novels in a row, but when I got to Descent of Angels, I read about half the book and put it down. I didn't come back to finish it until two months later. Descent of Angels has a few issues. First off, this story should not be set in the Horus Heresy. There is no Horus Heresy in this book. The entire story takes place well before the Heresy begins and Horus's name is only mentioned twice. Also, several events and characters are introduced which seem tacked on to the story. The purpose and details of these characters and events are simply not explained. Like many books, this one has an epilogue, but the epilogue makes no sense at all. It would have served better as the introduction to the next story then the ending of this story.
In the end, if you want to know the history of the Dark Angels, read this book. From what I understand, it goes beyond what the Codex covers. If you don't mind being a little frustrated and confused, its not a bad story, but it does not belong in the Horus Heresy series. I thought I would save you some time, by including a hidden summary of the book below. Highlight the text below to see a synopsis of the story.
The Dark Angels descend from a group of knights called the Order. After his discovery on Caliban by Luther, Lion El'Johnson quickly became the leader of the Order. The story follows the training of a recruit named Zahariel. Zahariel eventually becomes a full Knight by killing the Beast of Endriago with the help of psychic powers. While on the quest, Zahariel encounters mysterious hooded humanoids who tell him that he is tainted and he needs to leave the area. These hooded characters never appear in the story again. After a war with another group of knights, the Imperium and arrives and the Emperor himself makes a visit to Caliban. Zarhariel stops the assassination of the Emperor and is thanked personally by the Emperor. However, he will never remember it because a librarian erases his memory. After the Dark Angels chapter is reunited with their Primarch, they leave to bring some planet of humans who wear masks into compliance. These humans wear mask to hide some disturbing secret, but the secret seems to be irrelevant to the story because it is never revealed. These people delay the compliance process because the Chaos demon they worship tells them that the Space Marines are evil. Luther almost betrays the Lion and then the Space Marines fight and destroy the demon. The story ends with many of the Dark Angels being sent home in disgrace. No explanation for the disgrace is given, leaving readers confused.