DOTLAN EveMaps

The Thousand Sons were born of Magnus, the changeling Primarch. A physical giant possessed of coppery skin, fiery red hair and a single, baleful eye. Some say his massive size reflected his enormous intellect; his cyclopean eye his single-minded strength of purpose. At the height of the Great Crusade, Magnus was amongst the most imposing of the Primarchs and was always the one most suspected of taint. He would endure the whispers of Chaos throughout his life...

The progeny of Magnus the Red, the mystic Primarch who led his legion of sorcerers against the Emperor during the Horus Heresy, are the Thousand Sons.