Elena, Bonnie, Caroline and Louise

This is the sister-like relationship between Louise Gilbert, Bonnie Bennett, Elena Gilbert and Caroline Forbes. Louise, Bonnie and Elena were originally best friends, while Caroline was close to Bonnie, mainly due to being jealous of Elena.

Trivia

 * All four of them were different kind of supernatural creature.
 * Caroline as a vampire.
 * Bonnie as a witch.
 * Elena as a doppelgänger.
 * Louise as a seer
 * Louise, Elena, Bonnie, and Caroline have all died at least once at some point in the series. Elena has died two times, Louise has died three times, Bonnie has died four times, and Caroline has died once.
 * Caroline died in The Return when Katherine smothered her with a pillow. She returned in Brave New World as a vampire.
 * Bonnie died in The Last Dance when Klaus seeming forced her to use too much magic trying to kill him. However, she had really cast a spell to mimic death, allowing her to appear dead to Klaus, and magically return to life later in the same episode.
 * Louise died in The Sun Also Rises when Klaus drank her blood. She returned in the same episode thanks to a spell Bonnie had cast that allowed John Gilbert's life force to resurrect her, at the cost of his own life.
 * Elena died in The Sun Also Rises when Klaus drank her blood. She returned in the same episode as she drank Elijah's elixir.
 * Louise died in Before Sunset when Alaric stabbed her with a stake. She returned in the same episode as a vampire.
 * Elena died in The Departed when Rebekah caused Matt's truck to crash into the river, leading her to drown. She returned in the same episode as a vampire.
 * Bonnie died in Growing Pains from using dark magic to temporarily stop her own heart so she could travel to the Other Side and return Elena's soul back into her body. Unfortunately, she was stopped from completing the spell by the ghost of her Grams, and she returned to life through the spell in the same episode.
 * Bonnie died in The Walking Dead when she used too much magic at once to resurrect Jeremy. She was later brought back to life, in a sense, when she was made a corporeal ghost as the Anchor to the Other Side in Death and the Maiden.
 * Louise died again in Home, when she and Damon were blown up in an explosion as part of their plan to sacrifice dozens of Travelers to bring their friends back to life from the Other Side. She returned to life as a vampire after passing through Bonnie, just as they planned.
 * Bonnie died for the fourth time in Home when the Other Side finally imploded. She was surrounded by a white light as she and Damon were presumably sucked into another dimension.
 * They used to play near the well where Mason hid the moonstone on the Lockwood property.