Daemon

A Daemon is an intelligent entity of the Warp, and daemons are collectively the greatest servants of the Chaos Gods and of Chaos itself as a universal force. They are created at the whim of a Chaos God from a fraction of the God's own power and act as an extension of his will. A daemon's appearance and intrinsic character reflect the God's own nature. These daemons may be reabsorbed into the God's own psychic signature in the Warp at his whim.

Daemons in Realspace
Being an intelligent entity of the Warp (a dimension of the Immaterium), a daemon cannot exist for long periods of time in realspace, any more than a mortal can survive unprotected in Warpspace. There are a few ways a daemon can breach the walls separating the Warp from realspace and gain entry into the material universe.

Possession
Instead of being summoned into realspace, a daemon may possess the mind of a mortal (the mind of a psyker is the most susceptible to this, which is why the Imperium so greatly fears and controls psychic individuals), and turn the individual to its will and, through its host, affect reality. Some Heretics who serve Chaos Cults or the Ruinous Powers directly willingly offer themselves as hosts through daemonic pacts such as those pursued by the foul Possessed Chaos Space Marines.

Daemonic Incursions
In order to enter realspace in greater numbers, daemons need to use Warp rifts or Warp Storms. These are breaches in the fabric of reality that can vary in nature and size, such as the massive Eye of Terror or the Maelstrom. At times when certain conditions like the appearance of a Warp Storm or a sorcerous ritual have weakened the barrier between the Warp and realspace, a daemon can possess a mortal and turn him or her into a living portal through which whole daemonic hosts can pass for a time into the material universe. These daemonic incursions can taint realspace severely, often twisting and reshaping whole planets until they are lost into the Warp, becoming a part of the Immaterium and thus transformed into Daemon Worlds. It is not surprising that the Inquisition's Daemonhunters, the Ordo Malleus, are granted unlimited resources and political power by the High Lords of Terra to deal with such terrible threats to the continued existence of Mankind.

Greater Daemons
At the top of the daemonic hierarchy are the Greater Daemons whose immense power can be variable, depending on the whims of their patron Chaos God. Some, like Nurgle 's Great Unclean Ones, are only slightly less powerful than that of their patron God and in some cases they serve as temporary avatars of that God. Others, though immensely powerful by mortal standards, are allowed to embody only a fragment of the true collective power of their patron. Greater Daemons act as the wardens of their patron's realm in the Immaterium and have authority over the Lesser Daemons of their respective God. It is often they who lead daemonic incursions into the material universe.undefinedSuch is their might that they cannot simply be summoned by mortal Chaos Cultists performing a sorcerous ritual like Lesser Daemons. A Greater Daemon needs to possess a mortal's living body in order to fully manifest itself in realspace unless a Warp rift or Warp Storm has come into being, essentially eliminating the barrier between the Immaterium and the mortal world.
 * The Great Unclean One, Greater Daemon of Nurgle
 * Keeper of Secrets, Greater Daemon of Slaanesh
 * Lord of Change, Greater Daemon of Tzeentch
 * The Bloodthirster, Greater Daemon of Khorne

Daemon Princes
The most powerful mortal devotees of Chaos try to gain the attention of their Dark Gods in order to gain the terrible power and great rewards that the Ruinous Powers can bestow upon their most favoured servants. Those striving in the pursuit of their God's designs are known asChampions of Chaos, whose ultimate, driving goal is to transcend mortality itself by becoming a Daemon Prince. Those mortals who become Daemon Princes are counted among the most powerful of the servants of Chaos, second only to the Chaos Gods and theirGreater Daemons themselves. However, this path can as easily lead to another extreme. Throughout the path to power the Champion undergoes constant change, until either his patron Chaos God judges him worthy of daemonic ascension or his form finally is overcome by the accumulated mutations given through loyalty to Chaos and he devolves into a mindlessChaos Spawn.undefinedThe goal for most mortal Chaos Champions is to be elevated to the rank of a Daemon Prince in the service of one of the Ruinous Powers or of Chaos Undivided. This was the reward granted to the surviving Primarchs of the Traitor Space Marine Legions who fell to Chaos during the Horus Heresy.

Lesser Daemons
Lesser Daemons are the foot soldiers of Chaos, providing the core of the Daemonic Legions. They are usually anthropomorphic in appearance and possess a calculating, malevolent intellect. Among the Daemons of Chaos they are the ones most likely to answer the summoning calls of mortal heretics who engage in blasphemous sorcerous rituals to call forth these entities into realspace.
 * Bloodletters of Khorne
 * Plaguebearers
 * Horrors
 * Nurglings
 * Daemonic Steeds
 * Flesh Hounds of Khorne
 * Daemonettes of Slaanesh
 * Flamers of Tzeentch

Daemonic Creatures
These more primal Warp entities are the lowest type and least intelligent of the daemons. They are often granted as servants to other daemons and occasionally, one of the Chaos Gods' more powerful mortal followers or Champions. Daemonic creatures can be further divided in type between Daemonic Beasts and Daemonic Steeds.

Daemonic Beasts
Daemonic Beasts are driven by a feral intellect and commonly used as hunting beasts by the Forces of Chaos.
 * Beast of Khorne: Flesh Hound
 * Beast of Nurgle: The Beast of Nurgle
 * Beast of Slaanesh:Fiend
 * Beast of Tzeentch: Screamer

Daemonic Steeds
Daemonic Steeds are prized mounts used by the more experienced Champions of Chaos. Earning one of these creatures from the Ruinous Powers can be as dangerous as facing them in battle.
 * Steed of Khorne: Juggernaut
 * Steed of Slaanesh:Mount of Slaanesh
 * Steed of Tzeentch: Disc of Tzeentch

Unaligned Daemons
Apart from the four major Ruinous Powers that form the Pantheon of Chaos Undivided, there are numerous minor daemonic entities in the Warp who are Chaotic in nature too. The Chaos Gods tend to have less direct control over them, though they still serve the overall universal force that is Chaos.
 * The Fury, Daemonic Beast of Chaos Undivided
 * The Soul Grinder, former daemon of Chaos Undivided, dedicated to the Forge of Souls, an organization of daemonic smiths in the Immaterium which is independent of the control of any of the major Chaos Gods and uses the Soul Grinders to maintain that independence.

Daemonic Relationships with Mortals
Mortal worshippers of the Chaos Gods can interact with daemons in ways other than simply fighting alongside them.

Possessed Chaos Space Marines
Some Chaos Space Marines willingly allow daemons to inhabit their bodies so that they can enter the physical universe. Rather than the daemon completely taking control, as in the case of possession by a Greater Daemon, these Lesser Daemons form an amalgam of Chaos Space Marine and daemon commonly referred to as a Possessed Chaos Space Marine, or simply the Possessed. The Possessed are potent warriors, combining the abilities of a Chaos Space Marine with the sorcerous psychic powers of a daemon.

Closely related to the Possessed are Obliterators, which are mysterious, daemonically-warped Chaos Space Marines. They have become an amalgam of a Chaos Space Marine, a Lesser Daemon and heavy armor, and bear the ability to transform their bodies into powerful weapons, making them walking gun platforms. Obliterators have their own cult, which is most closely connected to the Iron Warriors Traitor Legion. It has since been learned by the Inquisition that the Obliterators were once the Techmarines of the Traitor Legions, horribly warped and transformed by their ten millennia of exposure to Chaos.

Daemon Weapons
Some daemons can be forced into servitude by being imprisoned within the physical structure of a personal weapon; these mighty artefacts of Chaos are called Daemon Weapons. Daemon Weapons are extremely rare, but also very powerful, often able to tear apart reality, shoot powerful sorcerous bolts of psychic energy, grant their wielder extraordinary physical attributes, or perform other such unnatural feats. A Chaos Warrior must exercise great caution with these weapons, however, as the imprisoned daemon will often try to rebel against its master and attempt to devour the wielder's soul.

Chaos Spawn and Daemon Princes
As a mortal worshipper of Chaos grows more powerful with each of his victories in the name of the Ruinous Powers, his patron God or Gods will sometimes reward him with mutational "gifts"; by the same token, with each failure, the God could also curse him with the same changes. However, the Chaos Gods are notoriously fickle and often bestow their gifts of change without rhyme or reason. These gifts can include mutations (such as extra arms, tougher skin, wings or the ability to shoot fire from his hands), equipment (such as exotic weapons or powerful armour), or even daemonic followers (such as the Daemonic Mounts). With each gift, the warrior becomes partly daemonic himself, being tied more and more to the will of his God and becoming more and more a slave to that entity's will. As a servant of Chaos continues to distinguish himself, and successfully carry out his God's desires, this individual will continue to receive Chaotic gifts. These gifts can grant the receiver untold arcane powers that will make him potentially as powerful as a Greater Daemon. As the Chaos warrior attains more and more gifts, he will ultimately face only one of two possible fates for a mortal in the service of the Ruinous Powers:
 * If the warrior receives too many gifts and is unable to endure any more, he can become a Chaos Spawn; alternatively, a Chaos Spawn could simply be any servant of Chaos who has spent too much time in contact with the warping power of Chaos or the Immaterium (perhaps through dwelling in the Eye of Terror), and has spontaneously mutated without the direct intervention of a Chaos God. Some particularly powerful Chaos Sorcerers have the ability to grant this dubious "gift" to a foe, instantly mutating them into a Chaos Spawn. A Chaos Spawn is a wildly mutated beast (meaning it can take many different physical forms as no two Chaos Spawns are actually alike), and has generally become insane or non-sentient, living the remainder of its existence at the whim of its God as the gibbering cannon fodder of the Forces of Chaos and a warning about the price of failure to all servants of the Dark Gods.
 * A particularly successful Champion of Chaos who is able to withstand the "gifts" of his God and successfully champion the goals of the Ruinous Powers on multiple occasions can eventually become an exalted Daemon Prince. A Daemon Prince is among the most powerful beings that can be found on the battlefields of the Warhammer 40,000 universe. They are frequently massive in size (much larger than a man and at least 10 feet in height), are very skilled warriors with the experience of hundreds of campaigns behind them, and have many powerful daemonic and psychic abilities. There are two types of Daemon Prince, those who have fully and willingly abandoned their mortal, physical form and have become a daemon in their own right; these beings can display many of the powers of a Greater Daemon, but specialized anti-daemon weapons and psychic powers can be used to banish these types of Daemon Princes back to the Warp. Then there are Daemon Princes who have not yet lost their mortal form; while still very powerful and infused with the psychic power of the Immaterium, they can still be killed by physical means outright, though they are immune to specialized anti-daemon weapons and psychic powers.

Daemonhost
Some especially Radical Inquisitors of the Ordo Malleus believe that one of the best ways to defeat the Chaos Gods is to turn their own followers against them. To this end, they will force a daemon into possessing a human body and, using powerful psychic spells, rituals and charms, bind it to the Inquisitor's will. These enslaved daemons are called daemonhosts, and they are sometimes brought to the battlefield where they use powerful daemonic abilities to destroy the Inquisitor's foes. However, such Inquisitors are seen as dangerous heretics by their more conservative Puritan brethren, and sometimes find themselves being hunted as though they were traitorous heretics themselves; by the same token, other Imperial forces will usually hesitate at the prospect of fighting alongside a daemon, as this is heretical in the extreme. The Grey Knights in particular despise the thought of these so-called daemonhosts, and refuse to fight next to such abominations to the will of the Emperor under any circumstances. Chaos Cultists and Chaos Sorcerors will perform the exact same ritual, albeit for a different purpose, in order to have daemons that are able to maintain a physical form, but still possess many of the strengths of a daemon. Certain Chaos Space Marine leaders, notably Abaddon the Despoiler, will bind his daemons in such a way that they possess little free will.

Daemon Engines and Daemonically-Possessed Vehicles
Daemon Engines are similar in nature to Daemon Weapons; they are special tank-like machines which are forged in the realm of the Dark Gods and controlled by an imprisoned daemon. They frequently carry powerful cannons which make them useful in sieges. The most common type of Daemon Engine is the Defiler created by the Traitor Legions since the end of the Horus Heresy, a large spider-like combat walker mounting the battlecannon typical of Imperial Guard main battle tanks like the Leman Russ. In contrast to Daemon Engines, daemonically-possessed vehicles are normal tanks and other Imperial armoured vehicles that have had a daemon sealed within them through the use of Chaotic sorcery, allowing it to control the vehicle in place of the normal Machine Spirit. This can be a strong advantage for the Forces of Chaos because the daemon, unlike a normal crew, cannot be killed or stunned by enemy attacks. The difference between a daemonically-possessed vehicle and a Daemon Engine is in the crafting - a possessed vehicle was built prior to its possession for a different purpose; a Daemon Engine has the daemon imprisoned within its structure as a part of the vehicle's original creation. Possession also comes in two forms: a normal daemon possession like that of a Possessed Chaos Space Marine, and a possession that is more akin to a parasite. Where the former daemon receives direct control of the vehicle, the latter will actually become the vehicle. With a parasitic possession the vehicle becomes a living being like the daemon, able to regenerate lost armaments or treads just as a living creature heals its wounds.