Elaine is a somewhat major character in the show. Despite her looks, she’s a centuries old fairy who was once guarding the fountain of youth. She’s also the sister of King.
And that’s how she meets the thief Ban. She easily outmatches him when he tries to become immortal. But he stays long enough around for her to fall in love with him.
And she dies when both of them are attacked by a red demon. Giving Ban immortality to save his life.
I do admit, his devotion to her was unreal. Even years later, he loves her and never wants anyone else. Determined to bring her back someway, somehow.
And his wish is accidentally granted when a demon brings back dead people with regrets. I did enjoy watching her unstable self fight Jericho. Though she eventually calms down to normal.
And Ban gives up his immortality to save her and to ensure her life doesn’t depend on a demon’s magic.
And they eventually marry and have a son named Lancelot. The Lancelot of Arthurian legend also had parents named Ban and Elaine. Pretty cool, huh?