Ancient pacts sworn between the Adeptus Mechanicus and the Adeptus Astartes allow the Space Marines to send those warriors with an affinity for technology to Mars to train and begin the long, arduous journey of becoming a priest of the Machine God. It is these Techmarines that maintain the weapons and equipment of the Chapter, ensuring that it is always ready for battle. A Techmarine can often be found on the field of battle, repairing broken vehicles and bolstering the defences of nearby buildings. While he is otherwise occupied, his Servitor bodyguards will either support him in his duties or lay down a withering hail of fire to discourage an attack by enemy forces.