|???? – 2012 (neutralized by Sam Winchester)
| 7.02 Hello, Cruel World
7.03 The Girl Next Door
7.09 How to Win Friends and Influence Monsters
7.21 Reading Is Fundamental
7.22 There Will Be Blood
Winchester. Congratulations. Apparently you two are competent enough to warrant annihilating. I’d take it as a compliment.
– Edgar, 7.02 Hello, Cruel World
Edgar from Missoula, Montana worked on a demolitions crew.
Edgar is working on his car — a Coronet 500 — when a Leviathan enters as black goo through his sink and possesses him. He goes to meet with another Leviathan — who is possessing a young girl — to discuss their next move and the "boss" they take their orders from.
The girl comes up with a plan to solve their feeding problem and steals the form of a doctor - Dr. Gaines - at Sioux Falls Hospital. It then uses the position to acquire easy meals. It's act of cannibalism is witnessed by Sheriff Jody Mills, who escapes the hospital with Bobby's help. Edgar arrives with the two gym student Leviathans, which tale on the forms of members of staff. Bobby investigates one of the bodies and is confronted by the leviathan Dr. Gaines, who recognizes him from before, when it was inside Castiel.
Bobby subsequently escapes the confrontation and races back home, informing the boys of his discoveries along the way. When they return to his house they discover it burned down and Bobby missing, however. Sam and Dean are then attacked by Edgar the Leviathan who informs them that they are considered "competent" enough that the head Leviathan wants them dead. The boys succeed in defeating him by dropping a car on it. Both suffer severe injuries, however, forcing Dean to call for an ambulance. Back at Bobby's, the black blood of Leviathan runs back into Edgar's body and its hand twitches as a sign of life.
After surviving the battle between Sam and Dean, Edgar is currently hiding out at a local restaurant when he receives a call from Chet, another Leviathan, telling him that found the possible location of Sam and Dean from a credit card purchase somewhere in Montana. Edgar simply tells Chet to follow up on this possible lead of where Sam and Dean are located. Edgar later receives another call from Chet confirming the location of Sam and Dean and that he plans to pursue them.
While Dean sleeps off the effects of the turducken goo, Sam and Bobby stake out the Biggerson's warehouse. A car pulls up and out steps Edgar, getting a hooded figure out of the trunk, and forcing him inside the warehouse.
The hooded figure is the Biggerson's waiter Brandon, and he has developed the same hyper-aggressive behavior as Gerald Browder. In the warehouse, Edgar greets the Dr. Gaines and tells him that he needs to be more careful because the adverse reactions that some people, like Gerald and Brandon, have to his formula are drawing attention. Dr. Gaines seems optimistic about his experiments, even his failures, but Edgar warns him that Dick Roman is coming and that he needs to burn his "mistakes." Later, he and the other Leviathans get sprayed with borax by the Winchester brothers who attempt to rescue Bobby who has been kidnapped to lure them there.
Edgar receives a call from Dick at one of their "slaughter houses" and later on, disguised as a police detective named Collins, easily kills two angels who bring Kevin Tran back home and retrieves the Word of God along with Kevin and his mom.
Edgar brings Kevin to Dick Roman who gets him to translate the Word of God for him after threatening to kill Kevin's mom. He then sends Edgar to pay a visit to the Alpha Vampire who has been tricked into thinking Dick is a friend and not a foe. Edgar arrives at the Alpha Vamp's house and waits for a vampire to show up. When he does, Edgar takes on his form to find out where the Alpha Vamp is and then kills him. He goes to the vampire's retreat and immediately knows that he has Dean and Sam prisoner, he can smell them. He then verifies what the Winchesters had told the Alpha Vampire: the Leviathans aren't allies with him and they are out to get every other type of monster (werewolves, shapeshifters, ghouls, etc.) who are all vulnerable to the Leviathan food additive. A fight ensues and Edgar gains the upper hand, even after being doused with borax. Just as he's about to eat the Alpha Vampire, Sam decapitates him. He and Dean leave after getting the Alpha Vampire's blood, but not before warning him not to leave Edgar's head close to his body for too long.