The Chosen are like this mountain, they are the foundation upon which our Chapter stands. It is by their labours that my battle-brothers are always ready for war. Chapter Master Pedro Kantor on the Chapter serfs of his Crimson Fists Chapter
The battle-brothers themselves are far too few to fulfill all the tasks required to keep the Chapter running at peak efficiency.
It is the Chapter serfs who perform most of these sometimes very menial but nevertheless vital functions, freeing up the Space Marines' time and allowing them to focus on training for and waging battle.
Most Chapter serfs come into the service of their Chapter by being drawn from the Chapter's homeworld population, being selected as aspirants of the Chapter but found wanting to become full-fledged Space Marines, or being born into that status as the child of prior Chapter serfs.
A minority of Chapter serfs are Humans who have been rescued by the Space Marines on the field of battle and allowed to accompany and serve their saviours out of gratitude. A Chapter's fortress-monastery is home to a large population of these hereditary servants and while they occupy a humble position, they are loyal members of the Chapter.
The serfs are inducted into the Chapter cult and customs, and do not generally begrudge the status they could have obtained if they were once aspirants, nor their lowly station, as they are always aware that their godlike masters could not fulfill their sacred duty of prosecuting the Emperor of Mankind's wars and defending Humanity without their humble but necessary assistance.
Chapter serfs are generally well-treated by most Chapters of the Adeptus Astartes, and are educated and trained to a much higher standard than most other servants of the Imperium in order to fulfill their duties. For instance, all Chapter serfs are capable of both reading and writing in High Gothic.
Amongst the Chapters of the Adeptus Astartes, individual treatment of Chapter serfs may vary: the Ultramarines and Salamanders treat their serfs the most fairly, as important if still mortal extensions of the Chapter, while the Imperial Fists tend to treat their serfs as if they were invisible and unimportant, while the Marines Malevolent treat them as little more than mortal slaves who are barely worthy of being in their masters' august presence.
When Space Marines go to war, their serfs maintain the fortress-monastery and defend it from attack. Chapter serfs are normally never deployed in battle alongside their Space Marine masters, whose battle prowess they could never hope to match with their frail, mortal frames.
However, most Chapter serfs are still trained in the martial arts to levels at least equivalent to that of a standard Imperial Guardsman, and are expected to assist in the defence of Chapter assets such as fortresses and vessels if the need arises.
Indeed, when the foes of the Emperor assault a Space Marine battle barge, it may very well be Chapter serfs manning the great vessel's gun turrets, freeing up their Astartes masters for more important tasks.
- Artificers - Artificers are Chapter serfs who are given basic training in the ways of the Machine-God by the Chapter's Techmarines, and perform the routine maintenance on all the equipment and wargear the Chapter uses, freeing up the Techmarines' time for the more advanced and arduous tasks.
- Master of the Refectorium - The Master of the Refectorium is the Chapter serf who is put in charge of the kitchens and food processing equipment of a fortress-monastery, and whose task is to ensure that food is always available to all the inhabitants of the Chapter fortress. Since enjoying a hearty meal is one of the very few mortal pleasures that Space Marines indulge in, the position of Master of the Refectorium is often a prestigious one amongst Chapter serfs.
- Medicae - The Medicae are those Chapter serfs who are given medical training and assist the Apothecaries.
- Monitors - Some Chapter serfs who are trained as messengers are known as Monitors. They undergo hypno-therapy that allows them to flawlessly memorise messages, and bury this information within their minds so that it can be reconstituted in whole only if they are given the correct verbal activation code.
- Ordinator of the House - This Chapter serf serves as the personal seneschal of the Chapter Master. This makes him or her "first amongst equals" and the nominal leader amongst all the Chapter serfs. This office can have many different names, depending on the culture and traditions of a given Chapter.
- Sacratium - Chapter serfs who tend to the Chapter relics and assist the Chaplains serve as part of what is known as the Chapter's Sacratium.
- Scribellum - Chapter serfs who assist the Librarians in writing down all the important deeds of the Chapter and its Astartes serve as a part of what is known as the Chapter's Scribellum. Part scribe and part artist, the Chapter serfs make sure the knowledge of the Chapter's past glories and tragedies remains at hand. They also assist in the creation of Purity Seals and similar texts of devotion.
- Brander-priest - A Brander-priest is a Chapter serf unique to the Salamanders Chapter. Each Salamanders Battle-Brother is assigned his own Brander-priest(ess), whose role is to brand his or her master's flesh with a red hot iron rod while reciting the sacred passages of the Promethean Cult. Brander-priests often become close confidents to their Astartes master, and usually immolate themselves on their master's funeral pyre when he falls in battle.
- Seneschal, Lictor and Absterge - These three Chapter serf offices are unique to the Excoriators Chapter. Each Excoriator Astartes is served by three personal serfs who assist him in all of his daily tasks. The Seneschal is responsible for maintaining his master's Power Armour and leather whip, the Lictor's main task is to flagellate his master's shoulders and back during the ritual of "Donning Dorn's Mantle" and the Absterge is required to dress his master's wounds and ensure food and drink is available when he requires it.
- Helmsmaster - The Chapter serf known as a Helmsmaster is unique to the Space Wolves Chapter. Unlike other Chapters, the Space Wolves have no Space Marine Captain in overall charge of the Chapter's fleet of warships. Instead, each Great Company has its own flagship, which is manned by Chapter serfs. The Helmsmaster serves as the Captain of the Great Company's flagship, and is trusted by the Space Wolves to deliver them safely to their objective, often in the midst of the enemy.
- Codex: Space Marines (3rd Edition), pg. 48
- Codex: Space Marines (9th Edition), pg. 16
- Codex: Dark Angels (6th Edition), pp. 14-16, 37
- Deathwatch: First Founding (RPG), pg. 106
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