|Heraldry is identical to each member's primogenitor Chapter.|
|Battle Cry||Unknown, likely nonexistent|
|Successors of||All First Founding Chapters|
|Successor Chapters||Multiple Ultima Founding Chapters|
|Primarch||All the Loyalist Primarchs (and maybe the others too)|
|Homeworld||Mars (Effectively, No homeworld was ever established)|
|Strength||About 20,000 at the time of the Indomitus Crusade's end, currently disbanded into the Ultima Founding Chapters and into other Chapters in need of reinforcements|
|Specialty||Great coordination and cooperation between astartes with different geneseed, being a massive pool of reinforcements during the Indomitus Crusade.|
|Colours||Pale Grey, with heraldry displayed on their pauldrons|
The Unnumbered Sons (full name being the Unnumbered Sons of the Primarchs, colloquially known as the Greyshields) are a Chapter of Astartes formed during Ultima Founding, during the Indomitus Crusade. Created by the Lord Commander of the Imperium Roboute Guilliman, this Chapter was comprised of only Primaris Marines, numbering around nine times legion-size. This unnatural size for a chapter is due to the fact that the Unnumbered Sons originally included the entirety of the existent Primarines, made with the geneseed of the nine loyalist primarchs, and made to work as a unit to improve the synergy between different chapters.
Origins of the Unnumbered Sons
After Archmagos Dominus Belisarius Cawl unveiled his 10,000 year project to Guilliman, the Imperium had thousands of these new Primaris Marines ready and available for use. The beginning of the Indomitus Crusade and the Ultima Founding meant that this massive force would have to be used on the battlefield as soon as possible. Thus, the Unnumbered Sons, famous for not wearing any chapter heraldry (having nothing drawn on their pauldrons and nor any colour on their armor, hence the nickname "greyshields"), were forced to push the tides of Chaos back and stop the 13th Black Crusade. During the duration of the conflict, Guilliman used this chapter to draw reinforcements and new chapters, reinforcing under-strength chapters with new blood and establishing entire primarine chapters. This, combined with the losses caused by attrition, meant that the Greyshields' numbers began to shrink fast.
By the time Roboute Guilliman declared the end of the crusade, around 20,000 Greyshields still existed. After the Battle of Raukos was over, Guilliman ordered the disbandment of the Unnumbered Sons, to either add them to already existing chapters or to create more new Astartes Chapters from them.