Tethering is the process of maintaining a physical presence in a dimension outside of your origin universe. The strength of the tether relies on a series of variables, and can be achieved through different means. The strength of the tether determines at what level the Demon can interact with the world itself.
Forms of Tethering
Physical ManifestationThis is considered to be the weakest form of tethering. Physically entering the Real World seems to create the weakest tether, causing the Demon to be heavily weakened or only able to exist in the world for a short period of time before being forced out of the world.
HostTethering to an physical object (such as a sword or a piece of jewelry) or an individual is the stronger way of lasting in the world, with the strength of the tether varying heavily.
Tethering to an object seems to vary in strength depending on the materials and whether it is in frequent contact with individuals. Jewelry has been observed in the past, with a decent tether but usually only as a means of transferring between individuals. A weapon may hold a better tether if it has been used, as the frequent interaction between the wielder and its victims strengthens the bond.
Automatons can also be tethered to, which provides a decent tether.
The strongest tether is through a living Host, with the strength of the tether increasing with the individuals willingness to let the Demon exist in tandem with them.
Possessing a HostFrom what we understand, a Demon initially tethers itself physically into the world, and has to find a Host to hold themselves to the world with. In the case of a living Host, they need physical contact and a willingness to let them in to take hold.
The strength of the tether relies on two factors: The Demon's exposure and familiarity with the world, and the willingness of the Host to allow the Demon to express itself.
The longer a Demon remains tethered to a world, the stronger it becomes connected to the world. This is most likely due to gaining familiarity with the physics and other physical laws of the land.
The Host can enable or suppress the Demon at will, meaning a kind of relationship between the two must be maintained. Until a demon is strong enough to overpower such suppression, a terrified host could suppress them to a point of having little strength in the world, while conversely a well acquainted duo with a great deal of time together in the world has the Demon at full strength, working in tandem with their Host.
The strength of the Tether also allows the Demon to influence the Host with their own traits, whether it is physical strength, some magical ability they can use, or by physically manifesting themselves temporarily outside the Host. We have observed Hosts extending claws, lifting objects well beyond their physical strength, summon weapons from the Demon Realm, and even double team an opponent with their Demon.
Depending on the strength of the tether, and if the Demon is in control, the Host will take on some of the visual traits of the Demon. This can range from markings on the skin/fur, horns growing in over time, a change in hair color, etc.
When a Demon speaks, you will hear both the Host's voice and the Demon's voice simultaneously, as their speech also causes the Host's lungs and voice box to imitate the motion.