Daemonhost

When I get out of here I am going to fuck you all up! I swear on my daemonic horns!

Daemonhosts are one of the most ridiculous ideas the Inquisition had came up with. Say thanks to Father Kelly, Mommy Mcneil and Uncle Chambers for this...'gift' kids (arguably Grandpa Abnett too, however whether Quixos deserves to be called an Inquisitor at that point and whether or not it was supposed to be a wide practice is up for debate). Daemonhosts are essentially the logical conclusion to Xanthism, for when using Chaos weapons, armour and Chaos sorcery isn't enough. Take a living mortal body and use it as a receptacle to bind a daemon, differing from a possessed in that the daemon does not possess or control the mortal, but is forcefully bound into it. The Daemonhost is then used by another mortal, often in order to use Chaos to fight Chaos. Because that always works well, though granted on occasion it can be very effective, provided the Inquisitor in charge isn't batshit insane or completely retarded about how much they should trust/watch/talk to a daemon (which is why these cases aren't the norm). It seriously seems like the Inquisition had stolen a page from Malal's book on fighting chaos.

Of course, if the Imperium was even slightly intelligent, they would have set up a Daemon Jail with this concept long ago, instead of banishing them back to their home.

Origins

The source of such bodies varies. Most times an end-justifies-the-means type Inquisitor of the Ordo Malleus will sacrifice inconsequential individuals so that they can bring forth a daemon that can be interrogated for information on Chaos. Or even more diabolically, they may use the Daemonhost to fight other daemonic creatures. The creation of a Daemonhost is considered heresy, and is enough for an Inquisitor to be declared excommunicate traitoris.

Some Chaos cults are also known to employ Daemonhosts as well, in case it wasn't obvious enough that this whole thing wasn't clearly heretical.

Process of Daemonic Heretical Rape

How possession normally works: Being an entity of the warp, a daemon cannot manifest itself in real space under normal circumstances. A daemon will usually enter the mind of a vulnerable psyker and turn the individual to its will and, through its host, affect reality. Outside of natural circumstances, and outside the Eye of Terror, daemons can exist temporarily in real space by being summoned through complex rituals. When a daemon manages to latch onto a person, the power of the daemon eventually takes its toll on the mortal body until it is consumed and destroyed, temporarily freeing the daemon that was possessing the person into realspace, until they get weaker, fade back to the warp and the whole cycle starts over again. Initially, the possessed may remain human in appearance, but over time the human form will be shift - its eyes will start to change, sometimes becoming blood red, or taking on the look of a cat's or snake's eyes, while the bone structure will be reformed, resulting in horns, bloating and other inhuman features until finally the hosts body is ripped apart and the daemon emerges forth.

Of note is that fact that it doesn't have to be a psyker that a daemon possesses. Chaos Cultists will often sacrifice themselves for "the good of the cause" so their patron daemon can lead them personally and if summoned as part of a ritual and with the use of sorcery it's possible to force a daemon to possess a random very (un)lucky cultist, and it can even happen if somebody's unlucky enough to get hit by the wrong warp/chaos made weapon, the injury (usually consisting of pieces of the weapon still left inside the unfortunate civilian) acts as conduit for the daemon to latch onto. Daemonhosts created by Chaos cults typically fall under this category.

The process of an Inquisition-made bound Daemonhost on the other hand is a lot more complicated and sounds like something out of a Dark Eldar BDSM ritual. The host must first be inscribed with certain marks, runes and wardings to prepare it for the entrapment of a daemon. The sigils involved are largely unknown to all except the attendees, but one rune usually considered essential is the rune called the "Rune of Voiding" which must be inscribed on the chest of the host in order to empty it of any previous souls so that the daemon can be effectively contained (and, you know, prevent the host's soul being eaten and destroyed). Apparently, this rune is sometimes ignored, as in certain occasions, the original host's mind endured. Once all the preparations are made, the Incantations of Binding, the Litany of Servitus, and the Wards of Entrapment must be spoken, along with the final sealing words: "In servitutem abduco, I bind thee fast forever into this host." Note that only these were mentioned by Inquisitor Eisenhorn in his logs, and that other rites might have been involved. If the ritual has gone well then the Daemonhost is forced to obey the Inquisitor (but will also secretly be trying to break free the entire time). Radical Inquisitors with the resources would also string the host with chains, padlocks, amulets, and other bindings as to ensure the daemon's obedience, failure to do so usually results in those Inquisitors being the first ones the daemon decides to take out its frustrations on. On the other hand, said bindings also make the Daemonhost less powerful, creating the temptation to weaken the bonds in order to make it a more useful weapon.

Of course this being the Inquisition, obviously the ritual (and later usage) of the Daemonhost must be kept secret as the answer on whether this is Extra Heresy at its most extreme is obvious.

If not all of the special preparations have been made, i.e. a hasty on-the-spot binding, the severe trauma of the process might be inflicted on the Daemonhost, ensuring that it remains docile and unresponsive for several days-or worse,the bindings can fail, allowing the Daemonhost to break free of its prospective master's control with predictable consequences.

Effects on the Host

The host also usually manifests psychic powers as a result of their close connection with a creature of the warp, sometimes so powerful that the host's body can barely contain it. They may appear to arc with electrical energy, cause minor air disturbances and often float a few inches from the ground. Daemonhosts also benefit from the invulnerability's of the daemon inhabiting its body, though the particulars may change from daemon to daemon. Some may only be harmed with silver, while others may be destroyed by sunlight. Some need to consume nothing but blood to survive. These traits may account for the stories of Vampyre cults that exist on some worlds in the Imperium.

It is possible to purge a daemon from a hosts body, leaving the individual free, but usually mentally, physically and sometimes spiritually scarred by the experience via an exorcism. While traumatic, the Inquisition has actually found this worth it and have even created an entire chapter of Space Marines who are forcibly made into Daemonhosts , before the daemon is exorcised from them because it usually has the interesting side effect of making the former hosts less perceptible to daemons to the point that in their first field test, the Exorcists achieved a 98/1 kill ratio on a daemon world. Unfortunately sometimes such a mark is made that the opposite happens, the individual is more susceptible to future daemonic possession, such individuals are usually executed.

Eventually, no matter how powerful a host's will, the experience of sharing a mind and body with a daemon will lead to insanity, effectively bringing an end to the life of the host, and allowing the warp entity to take complete control. In such cases, an exorcism may be of little benefit to the pathetic creature, and death will be the only mercy.