Eli

Ironically, Eli first met the Winchesters in Bloodlust when they came into his bar to order drinks, then ask questions indirectly trying to lead them to a nest of vampires - his. Sam pays him $50 for information, so he tosses out the Barker farm renters as rowdy, night owl people. Dean thanks him for the information, and they leave the rest of their beers. Later they are back in the bar with Gordon, celebrating the murder of Conrad, one of Eli's nest. Sam leaves early on, and Eli gets off work. Lenore had sent two vampires to grab Sam to bring to the nest. Eli grabs the bag off of Sam's head, before showing him his fangs and advancing on Sam. Lenore calls for him to step back, which Eli does, as she and Sam talk. Until Eli can't stand it - why explain themselves to this killer? They celebrated after murdering Conrad! Lenore tells him that's enough, which Sam echos. Lenore and Sam talk a little more, and she asks Sam not to follow them as they leave. Sam wants to know one good reason to believe her, and Lenore asks Eli to take Sam back without a mark on him. Eli and another vampire take Sam back, before returning to pack up to leave town. He confronts Lenore, stating they need to stay to fight - to kill in self-defense. Lenore is trying to reason with them, but Eli doesn't believe they can reason. She won't give up hope, and tells Eli to go gather the others from town because they leave before sunrise. He does so, meeting Sam and a tortured Lenore later. The nest leaves unmolested, just as Lenore had hoped and believed.

In Mommy Dearest Lenore, the vampire leader of Eli's pack, is brought to Dean and Sam for information. She tells them that Eve caused the rest of the pack, Eli included, to go back to drinking human blood.