<P> Damon has had a challenging relationship with his younger brother Stefan Salvatore for over a century . Before they became vampires, they both loved the vampire Katherine Pierce . Damon shows that he has nurtured a long - standing desire to reunite with Katherine throughout the first season . In the first season, we learn that it was Stefan who convinced Damon to feed and complete his transformation after Katherine turned both brothers into vampires . Despite the feud between the Salvatore brothers, both Damon and Stefan always have each other's backs . Damon is always there for Stefan when it really matters, e.g., saving him from being tortured, helping him through withdrawal, and working with him to kill common enemies . And Stefan will still give up his own life for Damon's survival . They both actually love each other but won't admit it, however: </P> <P> After learning of Katherine's deceit, Damon starts to fall for, Elena . In general, Damon is fiercely protective of Elena and always puts her safety ahead of all else . Damon comes to Elena's rescue at the Miss Mystic Falls pageant when Elena is left stranded without a partner, and the two dance . In the episode "Rose", Damon confesses his love for her only to compel her to forget about it because he doesn't believe he is worthy of her . Throughout the third season his relationship with Elena grows; she learns to fully trust him, and they begin to rely on each other as a team . They share two passionate kisses, but Elena remains in denial about her feelings for him . After a long struggle, Elena still chooses Stefan much to Damon's dismay . In the following season, however, Elena realizes that her feelings for Damon cannot be denied any longer . She and Stefan break up, and in the following episode Damon and Elena finally get together and have sex . Damon and Elena then both individually discover that Elena is sired to Damon, making Elena's feelings unfortunately known; however, Elena insists that her love for Damon is the most real thing that she's ever felt in her entire life . Damon remains doubtful, so in "O Come, All Ye Faithful" he sets her "free". In an interview before the season finale, Julie Plec stated that "This year, she's had a very traumatic roller coaster of life experience and it's changed her irrevocably--and at the center of it all was the diehard belief that she loved Damon, that she loved him more than she'd ever loved anyone ." In "Graduation", after the sire bond is broken and there remains no doubt about Elena's feelings, she reveals that she is in love with Damon . </P> <P> Damon and Elena spend the next few months together, having the summer of their lives . When Elena has to leave for college, Damon stays behind in Mystic Falls and they have a functional long distance relationship . However, in the episode "Original Sin", Tessa, who is revealed to be Qetsiyah, tells Damon that the doppelgangers are fated to fall in love and that he is only a bump in the road that makes their story interesting . Damon refuses to believe in this and assures Elena that he will fight for her and their future together as she is his life . It is later revealed that there is nothing fated about Stefan and Elena, but that they were merely drawn together by a spell . After a tumultuous, back and forth relationship, Damon and Elena get back together at the end of the season, and they choose to sacrifice themselves together to save Stefan and Alaric and their other friends on the Other Side . When Elena makes it back but Damon is trapped on the collapsing Other Side, Elena is devastated . Damon says his last goodbye to Elena, telling her that she is by far the best thing that has ever happened to him, and that being loved by her is "the epitome of a fulfilled life", as Elena sobs inconsolably . In season 6, Elena is unable to move on from Damon's death months later . She pretends to be happy, but she is secretly taking witch herbs to hallucinate Damon . When the herbs make her dangerous to humans, Elena decides to have Alaric compel away her memories of Damon, because she will never be able to move on otherwise . When Damon returns, he attempts to help her remember their love story, but the compulsion will not break . Not remembering any of the good things about Damon, Elena still decides to give him another chance . She slowly falls in love with him again, ultimately declaring that no matter whether she has memories of him or not, she always finds her way back to him . When Bonnie returns from the prison world, she gifts Damon with the cure for vampirism, knowing that he wanted to give it to Elena . However, Damon is afraid that this will mean losing Elena . They discuss what a human life together would be like . Elena initially rejects the cure, but Damon decides to take it with her so that they can have a human life together, including children . Damon always wanted Elena to have the human life she always dreamed of . Elena takes the cure, which breaks the compulsion, and her memories of Damon return to her . She recalls a memory from season 4, where Damon declares that there would be nothing more miserable than becoming human again . Elena is afraid that Damon would regret taking the cure, so she challenges him to think it through carefully . Stefan attempts to convince Damon that becoming human would be a bad decision, but Damon ultimately realizes that one lifetime with Elena is infinitely better than an immortal one without her, and confidently believes her to be his soulmate . Damon and Elena excitedly anticipate the beginning of their human future together, until Kai puts Elena under a sleeping spell, tied to Bonnie's life . </P> <P> Damon spends the next two seasons devoted to Elena, waiting for her to wake up . He repeatedly states that he is miserable without her, and will spend the next 60 or so years unhappily until Bonnie dies . However, Damon is committed to staying true to Elena, and doing right by her . Elena is shown to be Damon's moral compass, and his guiding force throughout the two seasons . When Damon is in the Phoenix Stone's version of hell, a vision of Stefan asks Damon "What would Elena do?" and this prompts Damon to forgive his mother, freeing him from hell . The phoenix stone's influence remains, and Damon accidentally lights Elena's coffin on fire (or so he thinks). Believing that he has unwittingly killed the love of his life, Damon becomes suicidal . When confronted with the hunter Rayna, Damon commands her to kill him because he is already in hell in a world without Elena . Enzo then reveals to Damon that Elena is still alive, renewing Damon's hope . When Damon realizes that he is a potential danger to his friends and family because he does not believe he is good without Elena, he decides to desiccate himself next to her . He write to Alaric that before Elena, he didn't know what it was like to be happy, fulfilled or complete, and that he doesn't want to continue living without that feeling . After Stefan wakes Damon from his desiccation, Damon continues to be devoted to his future with Elena . At the end of season 7, he is lured into a trap by a siren, hearing Elena's voice calling out to him . When the siren takes control of Damon's mind in season 8, Damon spends a significant amount of time sleeping, seeking refuge in dreams of his memories of Elena . When Sybil erases Elena from Damon's consciousness only to insert herself into their memories, Damon fights back, instinctively drawn back to Elena . His love for her prevails, and he breaks the siren's mind control, regaining his memories of Elena . Julie Plec stated that "I think the only hope that he's holding on to is the idea of the two of them living in Tribeca in their brownstone and raising kids and having a life together as humans when this is all said and done ." After Stefan gives Damon the cure to vampirism, turning him into a human, and Bonnie unbreaks the spell on Elena, Damon and Elena finally reunite . They begin their life together, getting married while Elena goes to medical school and becomes a doctor . Eventually they return to Mystic Falls to grow old together, where they died together of old age . We last see them walking hand in hand in the afterlife before reuniting with their respective families . </P>

When did damon turn his humanity back on