Without further ado, I give you my Flame Falcons.
The Flame Falcons
"Next to nothing is known of the Flame Falcons Chapter, for they were declared Excommunicate within a century of their inception. Initial combat trials involving the chapter were a resounding success, and they were put on active service on the Southern Rim, based on their new homeworld of Lethe. Their first engagements, with Orks and Eldar pirates promised a great future for the chapter, as they were observed to be hardy and courageous, even for Space Marines.
It was at the battle of Raffenburg's World that things began to go awry for the Flame Falcons. At the height of the battle, their largest engagement at that point, the first company were observed to spontaneously immolate at the height of the fiercest fighting against the rebel forces. Fearing witchcraft, the chapter's commander reinforced the front line and sent for an Inquistor who was accompanying the Imperial army. When it was reported by the reinforcing Space Marines that the members of the first company were not dead, but were in fact fighting with renewed savagery covered in flames to which they themselves were immune, the commander declared it a miracle, a gift from the Emperor.
The Inquisitor had a different opinion. Knowing that he could not assault the Flame Falcons immediately, he bided his time, witnessing the remainder of the chapter undergo the same change as the first company.
Upon the successful completion of the campaign, the Flame Falcons returned to Lethe in celebrant mood convinced, as they were, that their unique ability was a manifestation of the Emperor's grace. Soon after, the Grey Knights, at the Inquisition's behest assaulted Lethe, ruthlessly destroying the cursed chapter. It is thought that a small number of Flame Falcons escaped that day,but of their fate, nothing whatsoever is known." - Games Workshop Chapter Approved Annual 2004