Space Marines are genetic-enhanced and psycho-conditioned super humans loyal to the Emperor. They can do everything vastly better than any normal humans and can recover from wounds that are normally fatal. Although Space Marines are tiny in numbers, compared to the Imperial Guard, Space Marines are the most powerful and feared elite human warriors of Warhammer 40000.

Armed to the teeth, a Space Marine has access to the best weaponry systems mankind can offer that range from boltguns to Whirlwinds. Not only do they have the best weapons, Space Marines are equipped with advanced power armor can bounce off most attacks. This is not even including the super elite Space Marine Terminators whom are even further equipped with the very best armor and firepower of the Imperium.