Mind Compulsion is an ability possessed by original vampires, immortals, non-original vampires, and hybrids. It allows the user to control another person's mind by making eye contact, somewhat astral project into their dreams and overall 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.
Non-original Vampires can only compel humans, while Original vampires can compel both humans and non-original vampires, but not their fellow Original vampires (as Rebekah pointed out to Kol); and though non-original Vampires seem to be aware that they are being compelled while under the effect (Humans aren't), they are, by no means immune to it, unless they have Vervain in their system. However, any vampire can control the dreams of another vampire, like Katerina did to Stefan and Elena and what Damon did to Rose. Compulsion doesn't work if the victim is on vervain. In spite of that, Silas was able to entrance Caroline with a unique form of the skill. Interestingly, a Vampire who ingested vervain can still compel others without the vervain nullifying the effect.
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. To prevent compulsion, Elena wore a pendant which contained vervain, and Jeremy was also given a bracelet with the herb in it.
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.
Both of them also drink vervain tea. 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.
As Silas created the Immortality Spell for himself, and the fact he was a powerful psychic, the mind compulsion could come from Silas' original spell, to strengthen his psychic powers, and is why it would be present in the Mikaelson families version of his spell.
It is discovered that Bill Forbes cannot be compelled as he stated to Damon in Disturbing Behavior, and he said "it's a sort of human focus he's been honing for decades", so there is a possibility all humans could resist even though it could take a long time.
Species who can use this ability
All non Original Vampires possess the ability to compel humans and manipulate dreams and bestow hallucinations such as when Lexi made Stefan think he was lacking blood in Ghost World. They cannot compel other supernatural creatures such as werewolves however.
Due to their Vampire side Hybrids have the same exact powers of compulsion of a non 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.
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.
- Vervain - Wearing, holding, or ingesting vervain prevents compulsion. However, Silas seems to be exempt from this.
- Original Vampire Neutralizing - If an Original vampire is neutralized with the white oak ash dagger, any compulsion they have used on a vampire will be negated; this principle still applies if an Original vampire is revived by having dagger removed later.
- Limitations - Mind Compulsion can only be used on humans by regular vampires and hybrids, and only on humans, non-original vampires and hybrids by original vampires. Other supernatural creatures such as werewolves, the members of The Brotherhood of the Five and witches are immune to mind compulsion. Furthermore, it only seems to work via eye contact, and at a very close range, though more proficient users can perform it at a limited distance away from their victims, as almost every compulsion performed so far has occurred with the vampire using compulsion having their head right next to their victims as they compel them.
- Previous Compulsion - A vampire cannot undo the compulsion of someone who has already been previously compelled through a new compulsion.
- Transitioning - After a human turns into a non-original vampire, the compulsion wears off and the human begins to remember everything that was erased from their minds.
- Loopholes - Since Compulsion works by causing the recipient to be subservient to the specific commands issued to them by the Compeller, and that the Compeller can only issue any number of commands at any given time, it is possible to find flaws in the compulsion by exploiting loopholes.
- Mental Resistance - Humans with great mental strength can withstand compulsion, however only few humans have ever demonstrated this ability, most likely since it likely requires significant training.
- Magic - A witch is capable of delving into the mind of a being and removing the compulsion, however the process is extremely painful.
- The Anti Magic Barrier - Any human that was in the anti magic barrier, if they had been compelled the compulsion was undone.