Characters from The Vampire Diaries like Jenna Sommers, Stefan Salvatore, Camille “Cami” O Connell and others eventually perished forever in The Originals Spin-off.
When Mikael from The Vampire Diaries completed a task in The Originals, he formed a weak partnership with Klaus to defeat Dahlia, but when they failed, Klaus used the White Oak stake on Mikael again, reducing him to ashes forever.
Kol made his first appearance in The Vampire Diaries season 3, episode “Bringing Out the Dead”. He, like his brothers, was killed by Klaus and trapped in a coffin.
In the season 2 premiere of The Originals, it is revealed that Esther raised The Vampire Diaries’ Kol from the dead, placing him in the body of a witch named Kaleb.
At the end of The Originals series, Kol from The Vampire Diaries was one of the two surviving Originals until Rebekah takes the Cure (Freya is a Mikaelson but not an Original, and Marcel is an improved original but not a Mikaelson.)
During season 5 of The Originals, the Hollow’s dark magic threatened to kill Hope, and to save her, Klaus from The Vampire Diaries had the Saltzman twins extract the ancient evil from Hope’s body into his own.
Knowing that the Hollow would make him destroy everyone he loved in The Originals, Klaus from The Vampire Diaries resigned himself to ending his life by plunging the White Oak stake into his heart.
In the final moments of The Originals finale, Elijah revealed to his brother that his sole purpose in life was to witness the redemption of Klaus from The Vampire Diaries, and that he was ready to travel into the unknown alongside his brother.