The Brotherhood of a Thousand is a Codex Astartes-compliant Loyalist Space Marine Chapter of unknown origin and Founding, although the Chapter believes it is descended from the Ultramarines. Almost nothing is known about them in Imperial records.
The Brotherhood of a Thousand primarily wears grey Power Armour. The Aquila or Imperialis is golden. The white squad specialty symbol on the right shoulder guard designates operational specialty -- Tactical, Devastator, Assault or Veteran. A black Roman numeral is stenciled on the centre of the squad specialty symbol which indicates squad number. The colour of the shoulder plate trim indicates company number in accordance with the dictates of the Codex Astartes -- White (1st Company), Yellow (2nd Company), Red (3rd Company), Green (4th Company), etc.
The Brotherhood of a Thousand's Chapter badge is a black letter "M" on a slightly undersized white roundlet, centred on a field of grey. The Latin numeral "M" represents the number 1,000.
Originally the letter "M" was the Epic: Space Marine -- Great Crusade-era Legion badge of the Thousand Sons Traitor Legion, but this is no longer the case as their badge has been changed to the mystical icon, known as the Ouroboros (a snake eating its own tail).
- Adeptus Astartes: Successor Chapters (Limited Release Booklet), pg. 22
- How To Paint Space Marines (2004), pg. 86
- White Dwarf 98 (UK), "Chapter Approved: The Origin of the Legiones Astartes," pp. 12–17