Invitation is a weakness of vampires, hybrids and The Old Ones. In order to enter any house owned by humans, witches, werewolves or doppelgängers; they had to be invited by that person. Once invited, the vampire cannot be uninvited unless the ownership of the house changes.
This protection appears to manifest itself as an invisible barrier that automatically erects itself on the door lintels and any available entrance in a human home if a vampire tries to enter that dwelling without an invitation from the owner. The invitation may also come from someone who takes residence within that dwelling as they are, by extension, also received ownership from the actual owner(s). These barriers are extremely strong as they are among the few known ways to keep vampires at bay, if killing them is not an option. The barrier only holds for as long as the vampire remains uninvited, the owner(s) remain alive, and the dwelling remains standing. Because of this, vampires have been frequently known to resort to other methods to enter the house such as setting the house on fire to either destroy the home or to drive the humans inside out of the house and the protection it provides or by otherwise destroying the house. Vampires have been known to use this weakness to their advantage; by establishing a home with a human owner as to keep out other unfriendly vampires. It is somewhat unknown what happens to a conscious vampire who is in a human's home into which it was invited at the same time that the ownership changes. It seems unlikely that a fully conscious vampire can be forced into a house where it has not been invited.
Unlike their counterpart in television, vampires can enter homes when they are invited in by anyone in the house; regardless of whether they live in the house, are the owner or are a guest. However, if a house contains old structures of the original house along with renovated portions of the house that were added much later, the vampire must be invited into those parts of the house by only the original owners.
In the television series; if a vampire is in a house without a human owner or is invited in by the owner and then the ownership of the house is changed while the vampire is still in the house, the vampire will become disoriented and will begin to feel as though they are suffocating.
- The idea that vampires need to be invited to enter homes or residences has different meanings, but the principle is mostly the same (protection against undead).
- In some stories, vampires can not enter homes because it is inhabited by living things and it's like being underwater murky and full of life.
- In The Old Ones: The Beginning of the Immortals, vampires were not created by the planet compared to the other species. As a defense, nature attacks the vampires with sunlight, wood, vervain and other elements (water weakens the vampires in the books). With the purpose to defend against the undead, the living kept the vampires away by banning them entry into their homes. Literally, it's like saying: I invite my own death to my home.
- The origin of inviting a vampire into a home, it is on the novel by Bram Stoker. It is mentioned that Dracula was always invited to the homes; causing suspicion about this feature because in those days, usually people of high social class invite other people of the same class as a form of education and respect. Because Dracula looked like it, talked and moved like a person of high rank, he was easy to enter to homes.