The Space Marines Lore

The Space marines are genetically altered super soldiers originally comprised of 20 legions formed for the emperor’s children (The Primearch’s) for them to Lead. The space marines are 8 feet tall and use the most powerful of weapons, the standard issue Bolter is a normal small machine gun were as to a normal man has the power of a rocket launcher and is very large in comparison, a normal mans wrist would be broken completely due to the re-coil of firing even a bolt pistol and is not only the most common and simple weapon they have but it is considered Heresy for a normal person to touch a Bolter, the only non Astartis people allowed to poses a Bolter or anything more valuable are high ranking milatery.

Each space marine legion was made from the DNA of their primearchs with some carrying abnormalities that become actual diseases. The Ultramarine primearch Roboute Gulliman created the Codex Astartis which stated that instead of there being multiple legions that they would be organised into chapters that will be descended from 1st founding chapters that were originally legions, this was done to balance the power so that it would be nearly impossible for there to ever be an event like the Hours Heresy again and there are now hundreds of Space Marine chapters.