Mind Compulsion

Mind Compulsion is an ability of immortals, Original vampires, vampires and hybrids to control the mind of another simply through eye contact. Witches and sirens can also use this power though spells and physical touch, respectively, to facilitate a similar action. Thus far each species have been shown to have the ability to erase the victim's memories or even alter them to the point where something is completely different about them.
Compelled beings usually follow the instructions given to them by the vampire who compelled them to the best of their ability, sometimes even those that would otherwise be beyond their "normal" capacity (i.e. being forced to forget a very recent and otherwise unforgettable experience, cause them to develop new skills, and even create new personalities). Needless to say, this ability plays a vital role in keeping the existence of vampires (and by extension, other supernatural races) hidden. While most vampires use compulsion with verbal commands, this is not heeded as a necessity, as in one such instance Damon was able to compel Caroline with eye contact alone. However, this method of compulsion has not been used since. Silas however seems to easily do these feats without eye contact or verbal commands when he wants, and can even get into the minds of the Original vampires.
* Immortals can compel the minds of any species with the exception of supernatural hunters and passengers.
* Original vampires can compel both humans and non-Original vampires, but not their fellow Original vampires (as Rebekah pointed out to Kol).
** When an Original vampire dies, their compulsion wears off. This can also be achieved if they are neutralized with the White Oak Ash Daggers; this principle still applies if an Original vampire is revived by having said dagger removed later.
* The laws governing compulsion of Original vampires also apply to Enhanced and Upgraded Original vampires.
** However, with Vincent's aid as a witch, Marcel Gerard was able to compel Elijah, an Original vampire.
* Non-Original vampires can only compel humans.
** Non-Original vampires seem to be aware that they are being compelled while under the effect while humans aren't. However, they are, by no means immune to it, unless they have vervain in their system.
* Due to her status as a tribrid, Hope Mikaelson is able to compel other vampires; this is an exception seen only in Hope despite her status as a non-Original vampire.
* Witches, Supernatural Hunters, and Werewolves cannot be compelled by Original or non-Original vampires. However, Silas had the ability to compel witches as demonstrated when he did so to Qetsiyah and Bonnie.
* Hybrids can be compelled by Original vampires due to their vampire side.
* Compulsion doesn't work if the victim is on vervain.
** To prevent compulsion, Elena wore a pendant which contained vervain, and Jeremy was also given a bracelet with the herb in it.
** Some humans also drink vervain tea.
** In spite of that, Silas was able to entrance Caroline with an advanced form of the ability.
** Vampires who ingest vervain can still compel others without the vervain nullifying the effects.
* Some humans can train themselves to be immune to compulsion.
** In Disturbing Behavior, Bill Forbes could not be compelled as he stated to Damon "it's a sort of human focus he's been honing for decades".
** In After School Special, Atticus Shane could not be compelled saying that it was "something he picked up in Tibet".
* When someone is compelled, a new compulsion cannot override a previous compulsion.
** It is, however, possible to plant a new compulsion for so long as it does not conflict with the previous one. As users grow older, their mind compulsion skills evolve and mature.
* When a human who has been compelled in the past dies and is in transition to a vampire, they will remember everything they were compelled to do or forget.
* When a vampire who has taken the Cure and becomes human again, they can also remember everything they were compelled to do or forget by an Original Vampire.
** Anyone who was compelled by a vampire who has taken the cure will remember everything they were compelled to do or forget.
* Compulsion can be stripped away by the the Magic Purification Spell.
** A witch can also strip away the compulsion placed upon a vampire or human, though the process is painful and can be slow depending on how much or how deep the compulsion is rooted into the victim.
* A siphoner is able to remove compulsion by siphoning the magic of the compulsion allowing the person compelled to be free from compulsion.
* Compulsion seems to be tied to the user's spiritual essence since Klaus was able to use it while inhabiting the body of Alaric, a human.
== Species who can use this ability ==
=== Vampire ===
All non-Original vampires possess the ability to compel humans. They cannot compel other supernatural creatures such as werewolves, however. Most new vampires struggle to compel humans initially and it can take practice for them to master the skill. The length of time taken for a vampire to learn the skill, however, differs.
Vampires who solely drink animal blood may struggle with their compulsion due to their weaker state. On numerous occasions Stefan found it difficult to maintain his compulsion successfully due to his strict animal blood diet.
=== Hybrid ===
Due to their vampire side Hybrids have the same exact powers of compulsion of a non-Original vampire. That extends to all hybrids, but only those who are half vampire.
=== Original Vampire ===
Original Vampires have the same powers of compulsion as any vampire however they can compel any non original vampire so long if the vampire is not on vervain. They cannot compel each other though.
=== Immortal ===
Immortals are the strongest creatures on both shows mentally. They can appear as anyone and can compel without eye contact and even if the target is on vervain. Also they can compel a mass of people at once. They can inflict immense mental pain on targets such as when Silas convinced Klaus he was stabbed by the White Oak Stake.
=== Witch ===
Witches are able to achieve effects similar to compulsion through magic. The witch Maddox on one instance, controlled the actions of Carol Lockwood including what she spoke, making her mimic his actions like a puppet. After he was done, she did not understand why she did what she did. Several spells have also been used to make people forget, fall under a suggestible trance state and give false visions. Davina Claire once demonstrated the ability removing compulsion, however the process is extremely painful.
=== Siren ===
Sirens, like Immortals, are capable of some of the most potent forms of mind control and thus far, no means of removal have been demonstrated. Sirens are able to enter the minds of other people through Telepathy, allowing them to read their thoughts or access and alter their victim's memories, and to an extent their state of conscious and personality. Unlike an immortal's mind compulsion, a siren's victim is fully aware of their presence within their mind. This interaction creates a psychic bond between them, such that the siren can maintain a constant presence from within. This bond also serves to keep their servants close as should they stray too far the victims will be struck with psychic pain and suffer hemorrhages. Sirens initiate their mind control through use of their psychically enchanted voices at a baser level, with their control being as such that those whom have been 'sirened' would even readily set themselves on fire and end their lives. They have also been shown to be able to siren almost a dozen people at a time, seen when Seline used her power to siren the customers of a diner. Interestingly, vampiric servants have displayed the ability to provide some form of resistance to a siren's ability to penetrate the mind and manipulate the subconscious, but not from their control over them.