Spaces Marines are not simply mighty warriors they are also devout followers of the Emperor. They regard their mission to defend humanity against the myriad foes that threaten it as a holy one and they have absolute faith in the the Emperor. The first Space Marine Chapters were founded centuries before the development of the Imperial Cult and the dominion of the Adeptus Ministorum. This has led to each Chapter evolving its own unique religious practices and priests. These are the Chaplains who administer the rites of their Chapter and perform the ancient ceremonies of worship and devotion.

Chaplains have a vital role in the initiation of new recruits to the Chapter and in the constant affirmation of faith within the ranks of the Marines. Chaplains are amongst the most powerful of all the Space Marines. They accompany their brother Marines into war, chanting liturgies of battle, urging their fellows onwards with righteous zeal. They are invariably found in the thickest of the battle, exhorting their comrades to even greater acts of bravery.

Chaplain of the 3rd Company Ultramarines	Every Company has its own Chaplain. He acts as a leader in both devotions and battle. The Chaplain is more than capable of commanding the Marines in combat and is second only to the Company Captain in rank.
Chaplain of the 2nd Company Ultramarines

Chaplains wear black armour with Chapter icon and heraldry displayed on the left shoulder pad. Their badge of office is a white skull that generally appears on the right shoulder pad. Beyond this there is almost nothing else about their appearance that is standard. Each and every Chaplain is by definition a hero of the Chapter and will have fought in thousands of actions. Although they eschew personal honours their ancient suits of power armour are a realisation of the faith and victories of the Chapter, each one a revered artefact in its own right. Over the centuries the Chapter's artificers have constantly embellished these suits to glorify the Emperor and show the devotion of the Chaplain and his brethren.