Lost War

The Lost War is a little known campaign recorded in the Chapter annals of the Golden Knights Space Marine Chapter. Oddly, there is little extant information in regards to this forgotten conflict, other than the fact that it supposedly took place before the sundering the Space Marine Legions into separate Chapters and formation of the Adeptus Astartes.

Background
The only remaining records of the Golden Knights that dates prior to the Siege of Zintheron in 537.M38. Strangely, the dates found point towards existing prior the division of the Legions into various chapters. Not much information remains about this conflict and it is unknown where this battle even took place. The document makes several references to an Astartes only known as "The Lost Son" and a fight between him and the traitor Primarch, Fulgrim, before he disappeared, leaving the Astartes that fought with him upon the Maelstrom-class Galleas of War, The Redemption of the Lost. However, while the document confirms that this Astartes was not one of the lost primarchs, it does not give any information to who this warrior was, or from whom he was descended.