The Thousand Sons were the XV Space Marine Legion that the Emperor created for his Great Crusade. Their Primarch was Magnus the Red, and their homeworld was Prospero. During the Horus Heresy, they were accused of sorcery and attacked by the Space Wolves, so they turned to Chaos and fought against the Imperium. They have sworn allegiance to Tzeentch, the Chaos God of change, intrigue, and sorcery.
