The most well-known faction in the tabletop game Warhammer 40k is the Imperium of Man. They are our descendants in a dark and hopeless future and players can choose between a number of their forces to build their army and fight the hostile forces of the galaxy.

By the time of the 41st millennium, mankind has expanded its territory to distant parts of the galaxy. On worlds often far apart from each other the human population lives scattered in space. Through the technology of travelling through the Warp - a different dimension - it has been possible to reach all these remote worlds. The history of mankind is only legends and myths, while the truth has faded in time. Far in the past lies the Dark Age of Technology¹, a time of great scientific achievements and the peak of technological inventions. During this time the Warp Drive² was invented and psychic powers began to be explored further. The highly psychic Navigators came into being and were the only people who could guide a ship safely through the dimension of Warp space. The Dark Age of Technology ended in anarchy. With daemonic influences from the Warp, it became a war of destruction against the very inventions mankind itself had created. Many worlds became inaccessible during that war and the human homeworld Terra was a battleground.

Only the Adeptus Mechanicus - the Tech Priests of Mars - continued to explore the Warp and create new inventions while also maintaining the knowledge about how to operate the old devices. It is only due to their effort that Warp space travel is still possible in the 41st millennium, but real understanding has been replaced by rites and the belief in a spirit of the machine.

10,000 years ago the Emperor conquered Terra and reunited all humans in the Imperium, he was created as a leader and had lived secretly on Terra for millennia. The Emperor freed Terra's Solar System from alien forces and reintegrated the Adeptus Mechanicus. This made Warp travel possible again and led to the rediscovery of many human inhabited worlds. This process of reuniting human worlds and colonising newly discovered planets is known as the Great Crusade.

Unfortunately, the Emperor's highest Primarch, Horus, was influenced by Chaos and started a war against his own master. During the so-called Horus Heresey a big part of the Imperial forces became corrupted by Chaos. The Emperor was almost killed by Horus but managed to overcome him in the last minute. Since then the Emperor is kept alive by a stasis field on his Golden Throne on Terra. With his immense psychic powers he protects mankind and the galaxy from the daemons of Warp space and powers the beacon which the Navigators need for orientation in Warp. The Emperor is worshipped by humans like a god. In his name the vast bureaucratic network of the Adeptus Terra rules over all planets of the Imperium, his will is interpreted through special Tarot cards and seen in visions.

Whole planets are dedicated to the mass production of everything the Imperium needs. Hive Worlds are inhabited by billions of workers who spend their miserable lives in mines and factories, while other planets supply them with food. Forge Worlds are the factories where the Adeptus Mechanicus build their arcane machines. The forces of the Imperium stand together against the armies of Chaos from Warp space, alien races and corruption within the Imperium itself. It is a war for the survival of mankind in which individuals do not matter.

The Imperial Guard

We shall wage this war with undaunted faith and courage. We shall not take one step back. This is the Emperor's world and we will not surrender it!
– Lord Marshal Toshenko; Codex Imperial Guard, 5th edition

The Imperial Guard³ is the standing armed force of the Imperium and the biggest army in the galaxy. Its origins lie in the time of the Great Crusade, when the Imperial Army was founded. Later this army was split into the Imperial Guard and the Imperial Navy. While the soldiers are often rather badly equipped they can overrun the battlefield by billions. Daily, millions of them are recruited from the worlds of the Imperium and millions are killed in battle. The one thing that the Empire does not lack are human resources.

Due to the size of the Imperial Guard, there is a very complex command structure. Individual regiments are always built up from soldiers, officers and supply cadres coming from a single world and one or more off-world Commissars who have the authority over the whole regiment. They are transported together in one ship from their homeworld to a battlefield or guard post. Very often a regiment specialises in one form of battle which results in armies drawing their men from different regiments for greater variety. In addition to the billions of foot soldiers, the Imperial Guard also possesses tanks, aircraft and other machinery.

In a game of Warhammer 40k the Imperial Guard is a very flexible army. The player has many choices as to how they want to construct their army. They are rich in special characters with special abilities and their generals are customisable to a very high degree. They can be built up as an infantry or artillery army depending on the player's choice. An army of the Imperial Guard has a realistic command structure with some characters only functioning as leaders who actually give commands via radios. Every infantry platoon has a platoon command squad and a whole army is led by a general, his advisers and bodyguards. The player can customise their command troops in any way they like.

One standard unit of the Imperial Guard are not only regular soldiers like any other army, but is also built up of commanders, strong heavy weapons and special soldiers like sharpshooters. Another standard choice of the Imperial Guard are Veteran squads with better armour and weapons. Every unit has a wide range of different weapons to choose from and can therefore adapt to their enemy.

The Imperial Guard can have up to three times more tanks per army than any other army in Warhammer 40k. Their Elite choices are, for instance, sharpshooters and psykers and their own special Rambo character: Marbo. The Imperial Guard also was the first army with an aircraft in their standard army.

Additionally, there are a wide range of different human races available as models for the Imperial Guard, all having different uniforms and looks. These are, for instance, the soldiers from the fortress world of Cardia, the Catachan jungle warriors or the fighters from the desert of Tallarn, even cavalry is available.

The design of the Imperial Guard is based on various historic armies. In addition to 'standard' soldiers there are Russians with fur hats or even Nazis with gas masks, although some options can get rather expensive. Their tanks and other machinery resemble WWI equipment with a futuristic touch. All this makes the Imperial Guard look a little bit backwards and, although they do use weapons which are only available in science fiction, it is obvious that they are not really state-of-the-art in many cases.

The Space Marines

We are coming. Look to the skies for your salvation.
– Captain Kayvaan Shrike; Codex Space Marines, 5th edition

The Space Marines - or Adeptus Astartes - are the Imperium's genetically-enhanced elite force and are sent on the most dangerous and challenging missions. They are also a lot better equipped than the soldiers of the Imperial Guard. Protected by powerful servo armour and armed with heavy weapons they go into battle in much smaller numbers than the Imperium's main force.

When the Emperor conquered Terra he made use of genetically enhanced warriors for the first time. The Space Marines themselves were created during the Great Crusade and are genetic descendants of the the Emperor's Primarchs, who are themselves the genetically improved sons of the Emperor. Every Primarch took the command over his own legion of Space Marines. After the Horus Heresey the remaining Space Marine legions were divided into Chapters. Today the Space Marines are organised in about a thousand autonomous Chapters, each with their own spaceship and support staff. From time to time new Chapters are founded, each of them about a thousand Space Marines strong. Although all of them follow the rules of the Codex Astartes, every Chapter has their own view on these rules and spiritual rites. Every chapter has a base - a fortress-monastery - which is usually situated on a planet.

A player with an army of Space Marines can choose one Chapter of his preference. Some of them even have separate Codexes and therefore completely separate rules, others only have separate special characters of their Chapter. Each has their own heraldry and uniform colours. The most popular and certainly most famous Chapter, and even army, of the whole game are certainly the Ultramarines, the purest of all Space Marines, wearing dark blue armour with golden details and an upside down omega symbol. All colours and symbols are listed in detail in the Space Marine Codex, so a player can paint their army correctly. An Ultramarine with Heavy Bolter or Chainsword is certainly the best known miniature in Warhammer 40k. Even Games Workshop's main offices are guarded by a statue of a Space Marine, while the building itself bears the symbol of the Imperial eagle. By many, the Space Marines are also seen as the best army in the whole game. While this can be doubted, it seems true that 50% of all new releases for Warhammer 40k are made for the Space Marines. Games Workshop certainly always tries to keep their Space Marine players happy.

The Space Marines are probably the easiest army to play as they have a simple layout and tactics. They all wear heavy armour and have heavy weapons but as one army has fewer soldiers, it can be overrun by larger armies. Their long-range attack skills do not come up to those of the Imperial Guard, but they are extremely tough enemies in close combat. They also have a wide range of named characters.

Chapters with separate Codexes are the Blood Angels, the Black Templar, the Dark Angels and the Space Wolves. The Blood Angels, for instance, have faster vehicles and wear jump packs, which get them quickly into battle. Space Wolves have more special character heroes in their army and can use different psychic powers and they have wolf companions.

Space Marines started out as being just what you would expect of a space toy soldier: they were colourful, did not have as much detail as other models and were all in all slightly clunky. Similarly, their tanks and other vehicles seemed a bit less 'real' than the equipment of the Imperial Guard. With newer releases of Space Marine models this changed. They now have more details and are often heavily decorated with small items on their armour.

The Inquisition

To the righteous we bring hope. To the tainted we bring fire.
– Castellan Garran Crowe; Codex Grey Knights, 5th edition

The Inquisition is responsible for detecting and destroying enemies of the Emperor. It is divided into three major orders: the Ordo Malleus (daemon threats), the Ordo Hereticus (heresy and mutation) and the Ordo Xenos (alien threats). In times of need, an Inquisitor can call on any man of the Imperium and if everything else fails, can declare Exterminatus upon a world and destroy it completely.

The Ordo Malleus - the Daemonhunters - are entrusted with the task of finding and eliminating all daemonic creatures, the greatest enemy of mankind, from the Warp. To achieve this task, they have a secret chapter of Space Marines at their disposal - the Grey Knights. During the last days of the Horus Heresey, this brotherhood was founded by the Emperor himself and only the strongest and purest survive their training and rise in their ranks. They are equipped with the Imperium's best weapons from the Dark Age of Technology, arcane armour and the fastest ships in addition to their immense psychic powers. They only come in low numbers but are better equipped than any normal Space Marine army. The Grey Knight's fortress-monastery lies on the Saturn moon Titan, where new recruits are trained, their dead are buried and all their knowledge is stored. They even have daemons imprisoned in their fortress-monastery.

An army of Grey Knights can have Terminators, the Space Marines with the heaviest armours, in their standard troops. Their weapons are better as are the Grey Knights' own abilities and all of them have psychic powers. Their units basically all have the same equipment, with only slight changes for specialisation. Every Grey Knights army can have Inquisitors as their headquarters. The player can either choose a special Inquisitor with predefined rules or can make their own customised Inquisitor from a set of options.

With gleaming silver armour and shining energy swords the Grey Knights approach the deamon. Holy books and scrolls are hanging on their belts and all their equipment is inscribed with sacred texts. This is high tech exorcism. The core groups of this army can be built with only two simple, but expensive, kits.

The Ordo Hereticus - the Witch Hunters - are the Imperium's weapon against the internal threats of witchcraft, heresy and mutation. Its primary function was to keep an eye on the Ecclesiarchy, the state church of the Imperium. Its duties have expanded to control all internal threats of mankind. The Adepta Sororitas, the Sisters of Battle, entrusted with monitoring the church, became part of the Ordo Hereticus soon after its founding. The (exclusively female) Adepta Sororitas were originally divided into six independent Orders Militant, but smaller Orders were founded over time. Just like Space Marines, the Sisters of Battle wear power armour and carry heavy weapons. Unlike the Grey Knights, they are a visible force throughout the galaxy, protecting holy sites and pilgrim routes and forming the leading force of Wars of Faith of the Ecclesiarchy. Additionally, there are also non-militant orders of advisers, diplomats, physicians and nurses.

The Sisters of Battle are basically played like Space Marines but their models cost less points and they are not as tough. The Sisters of Battle can get bonuses from Faith Points which the player can split between the units in every round. They are great fighters at rather short ranges. Additionally an army of Sisters of Battle can also include members of the Ecclesiarchy and can even call their saints for aid on the battlefield.

The Sororitas very much resemble Joan of Arc in spirit and their design. They wear black medieval armour painted with white lily symbols. The Sororitas are some of the very few women in Warhammer 40k.

For the Emperor!

The armies of the Imperium can basically be divided into two types: Imperial Guard with its large masses of soldiers and tanks and the small, tough groups of the Space Marines and the Inquisition. Although they all belong to the same people the Imperials are diverse in their design and play style.

Unfortunately the only women in the whole Imperium seem to be the Sororitas, it is questionable why there are none as part of the Imperial Guard. This seems very unrealistic and sexist. Other manufacturers have tried to fill this gap with some rather dubious results.