To save the world from an onslaught of supernatural threats in The Vampire Diaries, Bonnie used magic to turn Silas to stone, allowing Damon to give Elena the Cure.
Despite Elena and Damon’s uncertainties about her future in The Vampire Diaries, she took The Cure while all the memories of Damon that Alaric had forced Elena to forget returned.
When a humanity-free Stefan appeared, the witch Bennett injected Stefan with the Cure, making him the first vampire to successfully transition to a human without drinking the Cure directly in The Vampire Diaries.
Fans of The Vampire Diaries thought it would be Damon, but were shocked to learn that Stefan injected his blood into Damon at the last minute and took his place. Stefan died a hero and was joined by his best friend Lexi in the afterlife.
Both Salvatore brothers were up to anything to save Mystic Falls, but Stefan injected his older brother with their blood and took Damon’s place in The Vampire Diaries. Stefan’s death ensured the defeat of Katherine and Hellfire.
Presumably, Damon was a better human than anyone expected. While the final moments at the end of The Vampire Diaries confirmed that he and Elena lived a happy life, the details were scarce.