From Lexicanum

The Badab War was one of the more serious rebellions in recent Imperial history, involving several Space Marine Chapters. Badab is a planet in the Ultima Segmentum, close to the border with the Segmentum Solar.

Badab's planetary governor and Master of the Astral Claws chapter was Lufgt Huron, known as the "Tyrant of Badab" in Imperial histories. The Mechanicus had long complained of the Chapter's tardiness in submitting the standard 5% gene-seed. The Astral Claws had as well amassed a huge debt in planetary tithes going back over a hundred and fifty years. In response to this, in 901.M41, an Imperial investigation fleet arrived within Badab's orbit. Almost immediately, a massive attack destroyed the fleet, the weapons fire coming from the planet.

This was Huron's first overt act of treason. Imperial records state that Huron was a power hungry and ambitious leader who never should have come to power within a Space Marine chapter. He was able in many respects, but lacked the absolute dedication to humanity vital in a Imperial leader. Imperial officials have suggested that Huron may have actually been an alien shapechanger, or that a sudden manifestation of psychic mutation was the cause of his treachery.

In 903, three other chapters had aligned themselves with the rebel Astral Claws. The Mantis Warriors, Executioners and Lamenters, along with the Astral Claws, attacked Imperial shipping across the sector. The Fire Hawks became involved when one of their ships was captured by the Mantis Warriors in 904; the Fire Hawks immediately retaliated, making the total involved chapters five.

To aid the Fire Hawks and bring an end to this insurrection, the Emperor recalled the Marines Errant from the Eastern Fringe; they found themselves occupied in protecting Imperial shipping, not able to aid in an offensive on Badab.

In 906, two more Space Marine chapters joined the battle, the Red Scorpions and Minotaurs, and the threat to Imperial shipping was almost eradicated.

In 907, the Red Scorpions and Fire Hawks returned to their duties in the galactic east, and the Novamarines and Howling Griffons were brought in take their places.

The Star Phantoms were given the task of besieging Badab, and two other chapters were sent to investigate the Mantis Warriors' and Executioners' home worlds. The Lamenters were caught in an ambush by the Minotaurs in 908 and eventually surrendered after bloody ship-to-ship fighting. After this, the majority of battles were sieges, leading to the eventual downfall of the Tyrant in 912 with the fall of Badab and final defeat of the Astral Claws.

Before the war was over, the Exorcists, Fire Angels, Salamanders, Space Sharks and Sons of Medusa were all involved in some way, replacing other chapters as they were needed in different sectors of the galaxy.

When the rebellion was defeated, the Mantis Warriors, Executioners and Lamenters were given the Emperor's forgiveness and reinstated as loyal Space Marines chapters, and subject to a 100 year crusade. The homeworlds of the Mantis Warriors and Executioners were forfeited to the Space Sharks and Star Phantoms for their vital roles in the war and the other chapters received salvage rights to the spacecraft as well as a share of the booty.

Astral Claws were all but destroyed. Only a contingent of about two hundred managed to fight their way through a blockage by the Exorcists and escape into deep space, taking refuge in the Maelstrom. Lugft Huron was one of the survivors. The Astral Claws changed their name to the Red Corsairs, becoming a pirate group, and Huron adopted the title "Blackheart".

Sources

• ¹Warhammer 40,000 Compendium
• ²White Dwarf 101(uk) "Index Astartes: The Badab Uprising" by Rick Priestley
• ³Cities of Death The Palace of Thorns