The Thunder Barons are a Renegade Chapter of Chaos Space Marines of unknown origin. Formerly a Loyalist Chapter of Astartes, they eventually spat on their oaths to the Emperor of Mankind and instead swore their allegiance to the Chaos Gods, and to the Blood God Khorne in particular. Since their fall to Chaos, the Thunder Barons have become obsessed with looking for amulets and artefacts of arcane power that will enhance their abilities in combat -- and provide more victims for the Blood God's pleasure.
- Cholercaust Blood Crusade (Unknown Date.M41) - The Thunder Barons joined the massive Khornate force known as the Cholercaust which followed the path of the Keeler Comet and brought war and ruin to the worlds in its path. The Cholercaust Blood Crusade was finally stopped by a small coalition of Imperial forces on the Cemetery World of Certus-Minor. The Thunder Barons and other Traitor Marines took to the field under the command of Lord Umbragg of the World Eaters and participated in the final attack on Obsequa City. The Cholercaust suffered a total defeat and all in its ranks were slain, including the Thunder Barons. It is unknown if the entire Renegade Chapter took part in the Blood Crusade, and whether or not Thunder Baron remnants still exist elsewhere.
The Thunder Barons' Chapter colours are not currently recorded in Imperial records.
The Thunder Barons' Chapter badge is not currently recorded in Imperial records.
- Daemon World (Novel) by Ben Counter
- Soul Drinkers (Novel) by Ben Counter
- The Legion of the Damned (Novel) by Rob Sanders