|Dates||???? - 2015 (killed by Dean Winchester)|
|Episode(s)|| 10.21 Dark Dynasty|
10.22 The Prisoner
Well, you got to be in it to win it, boys. You see, chaos breeds fear. Fear breeds panic, and panic breeds desperation, and there's always profit to be made from desperation. You make a big enough mess, has to get cleaned up. And we've been in the fix-it business for 1,000 years, and business has never been better. Now, for the last 80 years, we haven't had the book. With the book, we're unstoppable.
– Eldon Styne, 10.21 Dark Dynasty
Eldon Styne is the son of Monroe Styne, and brother to Jacob Styne. Like all members of the Styne family, he Eldon has had enhancements done to his body such as; implanting a second heart and adding extra muscles to his legs, allowing his body to be more durable and allowing for enhanced strength.
- "It's a family specialty. Bioengineering. Surgical enhancement. And I'm not talking about nose jobs. See? Two hearts in here. Bunch of extra muscle, especially in the legs. Every man in the family's had a little something. Pretty much what you'd expect, though, given the family tree."
A young student named Eileen, enters the office Eldon has been renting out for a research study on eyesight. When Eldon goes to give her a quick eye examination, he attempts to kiss Eileen, but she refuses his advances and screams "No" repeatedly, which catches the attention of the building's janitor. This prompts Eldon to take out a blade and slice her throat, while Eileen sits bleeding from her neck, Eldon quickly gets his surgical tools and removes her eyeballs before the janitor is able to get in the room. As the janitor finally opens the door, Eldon jumps from the third story window to the ground below and makes his escape.
In Shreveport, Louisiana Eldon is getting chewed out by his father Monroe Styne for being unprofessional and leaving a body and witnesses. Monroe threatens to turn his son into a lab rat unless he redeems himself by cleaning up his mess in Omaha and then tracking down he Winchesters. Eldon goes to Omaha and kills the building manager after he spoke to the Winchesters.
When Sam sends Dean out to get pizzas, Eldon and one of his men ambush him in an ally. Dean is able to get his knife and kill the henchman, however Eldon shows his superior strength by lifting Dean by the throat single handedly, Dean is able to regain control and take Eldon prisoner at knife point. In the Bunker dungeon, Eldon stands in the middle of the room, one arm chained up to the ceiling, as Dean threatens with torture if Eldon doesn't tell him what he wants. Eldon tells the Winchester what sort of business his family is in, as well as their true lineage. When Sam needs to leave the room to take a call from Castiel, Eldon attempts to make an offer to Dean -- hand over the Book of the Damned and they will have a discussion about removing the Mark of Cain. When Dean tells Eldon the book was burned, he tells that the it is protected by a spell and can not be destroyed; which prompts Dean to confront Sam. Before Dean can question his brother, there is a noise of a door slamming from down the hallway. Dean and Sam run down the hallway to the dungeon, where they see a trail of blood running out of the room. They enter to find Eldon’s arm hanging from the chain, in disbelief that he ripped it off.
Eldon is able to avoid being recaptured by Dean, and makes it to back alley. He gets a call from Eli who tells him he track Charlie down to the Blackbird Motel. Eldon makes his way to the motel and when he arrives the Styne cousins approach, though Eldon walks up and starts pounding on Charlie’s door alone. Eldon eventually breaks open the door, only to find an empty motel room. As he searches through Charlie's things, he hears a loud noise and figures out Charlie is in the bathroom. When he opens the door, he tells Charlie she's going to give him what's his and his family's. Charlie stands firm and pulls out a dagger, however Eldon is able to over power and kill her. Realizing the Book of the Damned is not in her possession, he leaves her body in the bathtub and makes his escape back to Shreveport, Louisiana.
- "The Winchesters dragged me to their - clubhouse. It’s filled with folklore, artifacts, maybe even the Book of the Damned. Now you give me a few guys, and I’ll make the biggest score this family’s ever seen."
After failing to get the Book of the Damned from Charlie Bradbury, Eldon suggests to his father they rob the Men of Letters Bunker for its stash of supernatural artifacts and watches as his younger brother, Cyrus is forced to harvest the boy who had been picking on him for spare parts. Eldon is then given the boy's arm to replace his own and takes Roscoe and Cyrus to rob the Bunker and then destroy it.
Knocking down the Bunker door, Eldon is pleased to see no one's there and orders the others to take what they can and burn the rest. As he prepares to burn a pile of books and Dean's things after making fun of them, Dean arrives soon after Roscoe staggers into the library with a knife in his back. Eldon taunts him about Charlie's death until Dean reveals he slaughtered the Stynes in revenge. Dean then tells Eldon that he may have many hearts and other organs but has only one brain. Not getting it, Eldon asks him "so" just before Dean shoots him in the head, killing him and avenging Charlie.