him "cold" and "arrogant". Sam eventually becomes addicted to demon blood, a fact that Dean soon discovers. With Bobby's help they lock Sam in a protected panic room so that he can detox, but the withdrawal symptoms are painful and he begins experiencing hallucinations. Just as the process becomes easier for Sam, Castiel appears and frees Sam. He meets up with Ruby and learns that he will need to drink more demon blood than he has ever done in order to have the strength to kill Lilith. Dean finds and confronts them and tries to kill Ruby, but Sam intervenes. He and Dean argue about how to stop the Apocalypse, whereupon Dean tells Sam he's changing into a monster, leading to a vicious fight between the brothers. Sam is the victor and as he leaves, Dean tells him not to return – just as their father John, years ago, told Sam not to return when he left for college. As Sam begins to feel the guilt over abandoning his brother, he and Ruby capture a demon that knows Lilith's location. Using his powers to torture the demon, she gives the location, but as Sam is about to drink her blood, the demon gives control to her human host, inciting immense guilt in Sam. A message from Dean, altered by the manipulative, arrogant angel Zachariah, manipulates Sam, pushing him to continue his original mission to kill Lilith; he then drains the woman of her blood anyway. Ruby and Sam go to St. Mary's Convent in Ilchester, Maryland, where they find Lilith. As Sam attempts to kill Lilith, Ruby holds the doors shut to keep Dean, who has just arrived, from interfering. Sam hesitates when he hears his brother yelling for him, but when Lilith mocks him for his inability to do the job – even after becoming a monster to do so – he finishes her off, fulfilling his true destiny as the "special child." Lilith's death breaks the final seal and begins forming a portal for Lucifer. At this point, Ruby reveals that she was leading Sam along the entire time so he would break the seal. Dean finally enters the room and kills Ruby with her own knife, while Sam holds her in place. Sam apologizes to his brother as a white light shows a portal beginning to open. Season 5 As the portal for Lucifer opens, Sam and