Thousand Sons

Magnus the Red's 15th Legion, scholars of forbidden sorcery.

The Thousand Sons are the 15th Space Marine Legion, led by the Primarch Magnus the Red, and their home world is Prospero. Reprimanded by the Emperor for dabbling in sorcery, Magnus and his Legion keep studying it in secret; when Magnus uses it to warn the Emperor of Horus's coming betrayal, he damages the Emperor's secret project, and the Space Wolves are sent to Prospero.

Background

After Prospero is razed, Magnus and what is left of the Legion take refuge on the Planet of the Sorcerers in the Eye of Terror. Their novel, A Thousand Sons, was in February 2010 the first Black Library book to reach The New York Times Best Seller List, at number 22.