Some Thought on the Adeptus Astartes

What follows are some of my thoughts on the Adeptus Astartes, and how they will be treated in Embers. 
 

The Adeptus Astartes are above all heroes, in a setting that runs on the Rule of Cool. This is reflected on all levels from most chapters methods of selecting neophytes, which would not be out of place as the beginning of a heroic fantasy book, to their attitude, origins and even the way they wage war. As such each Battle Brother is a hero in his own right, with the universe conspiring to allow him to make a greater impact, and to keep him alive unless he comes into contact with a greater story. This more then anything else is what separates the Adeptus Astartes from the other super-elite forces in the galaxy, and what allows feats such as a single tactical squad conquering a world.

While the Adeptus Astartes are incredibly varied, with members of one Chapter often having utterly different beliefs and attitudes to those from another if there is a single unifying belief it is duty. The Adeptus Astartes, well the loyalist ones at least, are duty bound warriors who will do the impossible if they must to fulfill their duties. In 40k that duty was mostly to protect the Imperium and to kill the traitor, the xenos and the deamon, in Embers it is mostly to survive, and protect some small fragment of the Imperium for as long as is possible, and often beyond that. 

In battle to face the Adeptus Astartes is to face an force of centuries old, super human heroes whose armour makes them effectively highly mobile tanks. When the superhuman physiology of a Space Marine is combined with their wargear and simple skill you get a foe who can shrug off anything that he can't avoid, can can reliably kill multiple veteran soldier a second and can fight for days without slowing. To make matters worse each Space Marine is a highly skilled warrior able to quickly adapt to changing circumstances on the battlefield in order to have the most impact possible. However the greatest impact is their nature as heroes, and how reality itself twists to make them the center of the story, even when numbers say they should be a sideshow.