|“||Expression is the manifestation of your will. You could do anything.||”|
Expression is a form of extremely dark and powerful sorcery that draws on energy that is so malicious it would supposedly demolish the world if it were ever called into existence. The details and history of expression remain unknown, however according to a witch named Nandi, the forces of expression are considered so powerful that many witches discredit it as magic, for it expands beyond the limitations of both ancient and modern witchcraft.
Damon and Stefan Salvatore travel to New Orleans where they encounter a witch named Nandi, who explained to the brothers the dangers and darkness of expression. Nandi informs Damon that her mother, Valerie LaMarche, tricked Damon into killing twelve innocent human beings in exchange for breaking his sire bond to Charlotte.
Meanwhile, Atticus Shane begins teaching Bonnie Bennett how to properly use expression, claiming that the magic was neither benevolent nor malevolent, but instead a neutral source of power that is not monitored by nature, and thus can be used however a witch sees fit. Whether this stands true or not remains unknown.
As the second set of sacrifices(hybrids) is completed, Bonnie's access to expression continues growing, as does her dark power. Unknowingly, she continues drawing from these sacrifices for power. The first time she actually starts believing it is truly dark magic that she is using is when in order to protect Shane from Kol & Rebekah, Bonnie accidentally, with the help of Qetsiyah's Talisman links April's life to Shane's, though he manages to convince her that expression is neutral.
The first time she experiences the true strength of expression is when she, in order to protect herself causes Kol great pain by snapping every bone in his body, something regular witches can not do to Originals. At the end of the same day, Bonnie manages to take down Klaus without any struggle and easily traps him in the Gilbert's House for 4 days, by biding the spell to the moon.
During the gang's trip to the island, Shane reveals to Bonnie that expression is what killed his wife, which angers the former seeing as he taught her the same magic that killed his own wife, though he claims he will keep Bonnie's power in control. Later,as she claims she cannot find a spell in Jeremy's tattoo, he replies by saying expression does not require written spells.
After Jeremy's death, Bonnie's magic slowly starts getting out of control after Silas is released. Silas,who seeks the destruction of the other side, manages to convince Bonnie to help him complete the expression triangle by killing 12 witches, to which her friends reply in shock, claiming that it is crazy.
During the events of Because The Night, it's revealed that Silas finally told Bonnie who he really is, as well as the fact that she needs to kill 12 witches to complete the expression triangle. Bonnie, completely unlike herself, immediatly agrees and tricks her mother's coven into believing that she wants to get rid of expression trough their help. Aja and her fellow witches link themselves and beging their cleansing spell, though Bonnie manages to hold them off from striping her expression,but is unable to fight their magic that is keeping her down. As they are about to kill her after learning Silas is controlling Bonnie, Caroline in a desperate move to save her best friend kills Aja, which in turn kills the other 11 witches too because of their link. Thus,the expression triangle is complete.
Later, it is revealed by Silas that expression can take a life of it's own if not controlled while Bonnie's magic gets more wild and unpredictable. The true extent of it's power is shown when Bonnie, after being attacked by a humanity-less Elena, heals herself more rapidly than either a vampire or werewolf would, showing as to why expression is considered unnatural, due to the fact that witches naturally can't heal at such a fast rate. Bonnie though learns how to control her power and manipulate it to her own will, seen when she manages to locate Silas without any of his belongings, a common necessity when performing locator spells.
Later on, Bonnie begans hiding from Silas after realizing he still wants to use her, much to his dismay. She formes an alliance with Katherine and promises to make her truly immortal if Katherine hands her over Silas' Headstone filled with Qetsiyah's blood. Though, hesitant at first, Katherine accepts but later on, as she breaks their deal, Bonnie links herself to Katherine, making sure that Silas doesn't get to her. One by one, the two go all over Mystic Falls, at the three points of the expression triangle, so Bonnie can channel it's power fully. First, Katherine finds Bonnie at the spot where Caroline killed 12 witches. Next, the two go to the place where 12 hybrids were killed and lastly, they travel to the farm where 12 humans died. As Bonnie channels the triangle, her power causes a violent wind storm to lash out in the town, as well as a power outage. Finally, in the center of the triangle, Bonnie drops the veil inside it, releasing spirits from the other side. She then begans working on invoking Qetsiyah, though Katherine's constant comments stop her.
Later on, after Silas attacks Bonnie and leaves, Grams appears, telling Bonnie that expression is a manifestation of a witch's will and an all-powerful force. Then, she proceeds to tell her she can too put Silas down as Qetsiyah did 2000 years ago. Bonnie, who is now self-confidant enough, goes after Silas to find him and just as she appears, Damon manages to take hold of him. Just then, Bonnie begins desiccating Silas or better yet, turning him into solid rock by clotting his blood and veins. As he tries to escape, Bonnie's power finally turns him fully into stone. Though, as she goes back into the cave to bring the veil up, she forms an idea that she could bring Jeremy back, much to her Grams' dismay. Not only does she use expression but also dark magic as well as spirit magic. Such a deathly mixture of positive and negative forces is too much and kills Bonnie which causes the veil to drop fully.
Though she still, despite her death proves to be powerful enough to trap Kol in the boiler room after tricking him into believing that she will help him. In the end, despite being dead, Bonnie still manages to use expression only and bring Jeremy back to life, much to her and his joy,but also his dismay when he finds out she died while bringing him back. Her last act before going to the other side is bringing the veil up.
- Damon Salvatore killed twelve unnamed human beings by the request of Valerie LaMarche.
- Pastor Young killed himself along with eleven members of the City Council at the request of Atticus Shane.
- Klaus Mikaelson inadvertently killed twelve rebel hybrids after being tricked by Hayley Marshall.
- Caroline Forbes killed twelve witches in order to save Bonnie Bennett from a ritual sacrifice.
- Expression is the most powerful form of magic known to man, however it is also the most dangerous.
- The sacrifice of thirty-six people creates an immensely powerful vortex known as the Expression Triangle. The Expression Triangle is so powerful, it is strong enough to bring down the Veil that separates the human realm from the spirit world.