Adeptus Custodes
The Adeptus Custodes are the personal guard of the Emperor of Mankind, for 10,000 years they have guarded the Emperor as he sat immobile upon the golden throne, having little involvement in the wars of the Imperium. Although since the return of the Ultramarines Primarch, Roboute Guilliman, son of the Emperor they have taken up a more active role in recent campaigns.