The Vampire Diaries thrived on romance, with the central love triangle between Elena, Damon, and Stefan. Of the two, Damon and Elena were in a forbidden romance because she was dating his brother, but nothing could keep them apart. Coined Delena by the fandom, the ship continues to have an enthusiastic audience today.
Source：https://www.cbr.com/vampire-diaries-damon-elena-delena-important-episodes/
