How can possessing human beings negate a daemon's immortality?

Question

Daemons inhabit a parallel reality known as the astral realm, and are separated from the mortal plane through an ancient barrier. This veil blocks beings above a certain threshold from crossing over, keeping vastly powerful creatures from crossing over willingly. Occasionally, gaps develop in this veil which allow ethereal energies from the outer plane to pass through. It is this that allow a daemon to materialize. Daemons must stay within the area which are covered by these energies, as they will get weaker the farther from it they go. When a daemon is defeated, it dissipates and returns to the realm from whence it came.

A certain sect that worships these outer forces believes that the highest honor a mortal can receive is to be possesses by a daemon. By serving as a host body for these creatures, they can reach levels of power unmatched by normal humans. The daemon also gains a vessel to contain it, no longer having to depend on infected areas and able to travel freely. it can now be used as a puppet by the daemon to conduct it's affairs.

The downside is that the daemon possessing the host dies permanently if it is defeated. I need a way to explain why a killing a vessel would kill the host and the daemon vs simply sending the daemon back to its plane of existence. How can I make this possible?

Answer 1

their existence is tethered to their plane.
You mostly answered your question yourself. Their power diminishes the further they move away from their area, suggesting the power they use flows through their portal. They are magically tethered through this portal to their own plane of existence. When they are defeated or mortally wounded this magical tether will pull them back.

When they possess a human, the tether is severed. They do no longer need the power from their own plane, as they can now use the life force from the human instead. Don't worry, humans have quite a lot of life force, so there is plenty to go around. And when the vessel does get burned out, hopping to a new one is easy as pie. The downside of this is, the daemon is no longer tethered, so when their body dies, nothing will pull them back into their own plane. Their existence is tethered to the life force of the human, and when this expires, so will the daemon.

Answer 2

You may be buoyant, but if you attach yourself to something which sinks like a stone, you do too.

The bond between the daemon and the human soul/mind/being means that when the human dies, the daemon carries on to the same place/non-place.

Answer 3

In order to possess a human, the daemon must allow the source of their power to inhabit them. This is different from manifesting as they use a tether back to their source to explore under their own power. They can still go back when possessing, it just takes a bit more effort to release the host by moving their source.

The advantage of moving their source to a host is: range, stealth, undiminished power. The disadvantage is that with their source removed from the original plane they must move their source back to escape instead of just releasing their grasp on a summoned corporeal form.

The advantage of a form created from a tear in the veil is that it is much simpler and much less risky than inhabiting a human. I suspect wiser and stronger daemons would avoid possession due to the risk while small fry daemons would flock to attempt to possess.

A wise, strong daemon with a human host would be quite a force to contend with and would only attempt such a thing in either dire or extremely profitable situations.

Answer 4

Possession Tethers a Daemon's Soul to a Human's

The rituals of possession bind a demon's soul to that of a specific human. This is what allows the demon to overrides the human's control of their body and memories. As a normal process, there are rituals the daemon can enact to unbind themselves to find another host or return to the astral plane.

If the demon's soul is still bound to a human's at the time of death, it follows the human soul to the afterlife. If this doesn't constitute as death, whatever being / process that controls your afterlife destroys them.

Answer 5

If you're working with a concept like souls in your story, I would suggest you make the link between the daemon and the possessed permanent in some capacity.

I can come up with two ways this could work.

Either the demon uses the human vessel as a container for the demonic energies it needs to survive in the human realm so it doesn't 'starve' while away from the energy hotspot.

If that's not something you feel fits your story, then perhaps having both possessing a human as well as leaving a possessed human bound to a ritual could work? I'm thinking leaving needs to be something they can't just do when they realize they're about to die, because then there wouldn't really be a point to the disadvantage, would there?

Anyway, I hope I was helpful in some way! To you or others. Happy writing.

Answer 6

The main reason a daemon wants to possess a host is to be able to move freely to places with no source connection. But this is deadly for an unprotected daemon.

If the host dies near the source, then the daemon will survive, same as without a host. But there is no point in possessing a body if you just stick around the source - so the daemons that possess the bodies pretty much all leave the source to explore the world and exert their influence on it. And if the host dies far away from the source, then there is nothing nearby to pull the daemon back to its plane. The daemon simply dissipates.

Answer 7

Daemons Blend their life Energy with the host, changing both the Host and the Daemon.

I realize this is quite similar to some other answers but lets get into how this happens.

The Daemon acts like some sort of Parasite. It enters the host, severs itself from the energies of the other plane allowing it to move about free of the rift, and it can take greater action in this plane. That makes the potential downside risk of dying worthwhile. Now, if it were a one way ticket, then the downside is too great. But if you leave open the possibility of the Daemon to move from one host to another if done properly, or if it can return to the other plane if it gets close to the rift and attaches itself to the energies again, then the gamble of possessing a mortal becomes much more attractive. That covers the reasons.

Now for the mechanics. The Daemon gives up the connection to the other plane in order to infect or Posses the host. It links it's essence to the essence of the mortal host. They blend very tightly. It takes a Ritual to do this, another ritual to separate from one host and move into another, and yet another to leave the host and return through the rift. In each ritual where the Daemon leaves a host, it will rip the life force out and kill that host. It does this to preserve itself until it can move to another host or until it can reconnect with the energies from the rift.

Now, because the life force of the host and the life force of the Daemon are so tightly blended that if the Host gets killed and there is no ritual to safely separate the two, both Host and Daemon will die, moving to whatever destination plane the soul of the host is going to. It won't be here, and it won't be wherever the Daemon came from. So from a practical standpoint, the Daemon is dead.

One thing that could be interesting is that in many bits of folklore, the creatures from elsewhere are immortal and unchanging. The same folklore sometimes stresses that only humans are capable of true change. When the Daemon and Human blend their life force, the Daemon can now be changed. The Daemon that moves from the host to another isn't exactly the same as the Daemon who possessed the host in the first place. The Dresden Files books has a good explanation of this dynamic with a Fallen Angel in Harry Dresden's head (for a few books, anyway).

Answer 8

perhaps a simple analogy would be putting a finger or such into water... this is a Very different plane of existence overall, but if the water was to freeze suddenly or become acid, you're finger is toast!

an entity that moves it's essence into another being that's a conduit to another realm wouldn't be different than losing the ring that was on that lost finger. That brings up the idea of what was still in the first realm, and ideas of heaven or such that the host is connected to, so what do those overlapping relationships between realms look like?

Answer 9

Frequency and Resonance

NB: This is not intended to be a hard science answer, I realise I may have butchered some of the terms I've used.

These daemons are beings of energy, their host dimension has a natural background frequency which they resonate with.

Near the gaps between daemon and human dimensions, this background signal is dominant. But further into our dimension and away from the gaps, this signal starts getting distorted and this dimensions frequency becomes dominant.

Think of two radio towers seperated by some distance playing different stations on the same wavelength. Your radio will pick up the one with the strongest signal (the nearest one) but somewhere in the middle of the two towers, you'll just pick up garbage.

Moving into the area where the daemon signal gets distorted, causes the demon pain, moving beyond this area where the human dimension signal becomes dominate and the daemon dissipates.

So what's a daemon to do? Find a portable radio transmitor of course. All living creatures generate their own electrical fields, but a daemon needs something human sized. Anything to small and the daemon short circuits the creature, to large and they can't influence the creature.

It may be the case that a daemon may need some time to fine tune the potential host's frequency before hopping on board. This raises the possibility that some humans are more susceptible to possession and some daemons are better at it than others.

Once fine tuned, human and daemon frequency generate a wonderful resonance, meaning that the daemon's host can now do things it wouldn't normally be able to do. Better strength, speed, stamina and senses. It may also be able to project energy fields for different purposes, such as confusing other people nearby with low frequency waves or causing people to suffer from vertigo.

However, if that host dies, so does its electical field. And if the daemon is far enough away from it's source frequency, then its own energy dissipates, essentially dying.

Answer 10

The soul of the human and demon must knit together for the ritual to work the human is given it's body and controls to the demon in exchange for power a deep wiring is done to allow the power to manifest and for the controls to even be touched so the demon is giving up it's shapeless form to not just feel sensations but also to gain a vehicle and sanctuary to do some desired task.

Maybe there is a separation ritual that is long, slow, and needs uninterrupted time for the two to split up but after one gets the taste of the other their minds are blown so much they do not desire this maybe only after the vessel has aged so long will they both "divorce" on good terms the human knows they will die soon and doesn't want to kill off the thing that has given them whatever positive, negative, or neutral powers they craved and so release it for another to be reformed by this demon.

The demon if it chooses not to separate from the human dies with it a deep act that's probably more then controversial in its own plain was it love? Was it insight into the futility of immortality? Who knows but the pair was altered when the demon took hold of the human binding both to the mortal realm so if death is to occur unnaturally via violence or sickness the demon must be along for the ride it's the demons job to secure the body after all as it gave the powers to the human for mutual cooperation.

Answer 11

Human afterlife won't accept a daemon soul and daemon afterlife won't accept a human soul. You mentioned there was a wall that blocked passage between the two areas. When you die with an entwined soul it basically just doesn't know where to go and gets lost in the void.