Eileen Leahy was the only daughter of Padraic and Maura Leahy. During a Banshee attack in her house in 1985, due to the Banshee scream, rendered her deaf. An Irish hunter, Lillian O'Grady, who had tracked the Banshee, later found Eileen and her slaughtered family. She was raised by O'Grady, and trained to be a hunter until her died when she was sixteen years old.
During a Banshee attack in Oak Park Retirement Living, Eileen learned that it was the same Banshee that had killed her parents is involved in here, and posed as a janitor to hunt it. She later met Mildred Baker who was a resident at the home.
She initially falsely believed that Sam and Dean Winchester were the Banshee she was hunting and were posing as FBI agents to hide their kills. After following Sam, she trapped Sam with a Celtic spell and was about to kill him. After Sam convinced her he was a hunter, not a Banshee, she disabled the spell and released Sam.
She later told Sam that the Banshee that Sam and Dean were hunting was actually the same one that was hunted by her mentor, O'Grady, and that her family was slaughtered by it. Her mother, Maura, was the daughter of a Man of Letters who was sent to Europe.
At night, she and the Winchesters created a plan to kill the Banshee by using Mildred as bait. The Banshee managed to overpower them, and targeted Dean as the vulnerable one instead of Mildred like they had planned. Thanks to Mildred's activating the Celtic spell, however, the trapping spell activated and the Banshee was trapped. Eileen killed it avenging the death of her parents.
With her revenge fulfilled, she later chose to continue on the hunter's path, like her mentor.
Power and Abilities
- Spell Casting - She was taught by Lillian O'Grady a spell that could render nearly anything to be trapped in its vicinity.