<P> Stefan and Elena begin a relationship and he revealed to her that he is a vampire . However, Damon returns to Mystic Falls, too, and also falls in love with Elena . Further on in the series, Damon and Stefan start to bond as brothers again and it becomes apparent that they do love each other . Because of his addiction to human blood, Stefan only drank animal blood in the beginning of the series, which made him weaker than other vampires . In season two, Stefan starts to take small amounts of Elena's blood each day to mitigate its effect on him and to increase his strength . When Katherine returns it is discovered that she had always loved Stefan and not Damon; however, Stefan is in love with Elena and not interested in Katherine . Stefan starts to build a friendship with Caroline Forbes after she is turned into a vampire . After Klaus gives Stefan his blood to save Damon from a werewolf bite, he turns Stefan into a Ripper again . </P> <P> Stefan starts working for him as he agreed to do to save Damon, and hopes it might also protect Elena by making sure Klaus never returns to Mystic Falls, since he believes her to be dead . Klaus later finds out and compels Stefan to kill her, but when he is able to resist the compulsion, Klaus makes him turn his humanity and emotions off . However, he is later able to get his humanity back, which is seen when he saves Klaus's life to protect Damon, but yet he pretends not to care about Elena anymore . He then takes it upon himself to kill Klaus . He steals Klaus's family as retaliation, and uses them as blackmail, when that fails (the witches give Klaus the coffins when he threatens to end the Bennett line), Stefan threatens to drive Elena off Wickery Bridge with vampire blood in her system if Klaus doesn't get his hybrids out of town, Klaus agrees at the last minute . He and Elena get into a fight . In the season three finale, he kisses Elena . In the end, Elena chooses Stefan over Damon, but when Rebekah causes Matt's truck to drive off Wickery Bridge, she is trapped underwater . Stefan barely gets there in time, but Elena makes him save Matt first and she drowns . It is later revealed Dr. Fell gave Elena vampire blood, meaning she died with vampire blood in her system . Then she became a vampire . </P> <P> In the season four premiere, Stefan tries to get Bonnie to save her from becoming a full vampire, however, she along with several other vampires are captured by the Founder's Council . As Elena begins to die and out of desperation to keep Elena alive, Stefan kills a guard and uses his blood to allow Elena to feed and to complete her transition into a vampire . Stefan gives Elena a daylight ring, which was made by Bonnie, in order to protect Elena from the sun . Stefan tries to assure Elena that everything will be okay and that they'll take Elena's newborn vampirism one day at a time . During the second episode of season 4, Stefan tries to help Elena cope with her hunger for human blood . After his "bunny diet" disagrees with Elena stomach she seeks help from Damon to find an alternative blood source . When blood bags and Damon's own blood fails too, she ends up feeding on Matt under extreme circumstances . Stefan then discovers from Klaus and Rebekah that there is a possible cure for vampirism . Stefan "teams" up with Klaus in order to find the possible cure, so that Stefan can give Elena the choice of becoming human again . </P> <P> Unfortunately, Klaus needs the vampire hunter Connor to stay alive because he holds the map to the cure in his tattoo, and Stefan must keep him alive at all costs when everyone else wants him dead . When Connor kidnaps Jeremy, April, and Matt, and keeps them hostage at the Grill, Stefan must stop Damon from rashly walking in and killing his chance at curing Elena . After tranquilizing Damon with vervain and taking his daylight ring, Stefan tries to take matters into his own hands and infiltrates the Grille by himself . With Jeremy at gunpoint, Elena comes in and takes Connor by surprise . Stefan manages to get Connor out, but Elena later kills him and is consumed with grief at being a murderer . </P>

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