The Leahy Family was an Irish family with connections to the Men of Letters and the world of hunting.
In 1939, American Men of Letters representative Edward Durbin II came to Europe as part of a delegation. While there, he ended up having a daughter named Maura. Maura would eventually marry Padraic Leahy and they would have a daughter together named Eileen.
Padraic eventually lost his job and as a result, suffered a nervous breakdown. Though he was recovering from his breakdown, this left him vulnerable to a malevolent Banshee that came to the house in 1986. Recognizing what was after her husband, Maura performed a banishing spell for the Banshee. Maura was unable to save Padraic and the Banshee targeted Eileen. Maura managed to banish the Banshee and save her daughter's life, but lost her own in the process. The attack also rendered Eileen deaf.
Following the loss of Padraic and Maura, Eileen was found by a hunter named Lillian O'Grady who had been after the Banshee but had failed to catch it. Lillian went on to raise Eileen and train her to be a hunter before Lillian died of cancer when Eileen was sixteen. Now on her own, Eileen continued hunting with the desire to find the Banshee that killed her parents and get revenge upon it.
In 2016, the Banshee that killed Padraic and Maura attacked the Oak Park Retirement Living home in Lebanon, Kansas. Eileen tracked the Banshee to Oak Park while the Banshee's first attack drew the attention of hunters Sam and Dean Winchester. Upon realizing that they had a common enemy, the Winchesters and Eileen teamed up together to kill the Banshee. With the help of Oak Park resident Mildred Baker, Eileen was able to trap and kill the Banshee, avenging Padraic and Maura. Even though she had her revenge, Eileen chose to continue hunting and helping people.
In 2017, the Winchesters enlisted Eileen's help in tracking down Kelly Kline. Eileen was able to help the Winchesters and British Men of Letters operative Mick Davies track Kelly, but the group came under attack by the Prince of Hell Dagon. Eileen tried to kill Dagon with the Colt, but missed and instead accidentally killed British operative Renny Rawlings. As a result, Eileen decided to return to Ireland for the time being while British Men of Letters Elder Doctor Hess ordered her death.
Realizing that she was being followed by the British Men of Letters, Eileen returned to America and attempted to seek out the Winchesters for safety. However, she was ambushed by Arthur Ketch and killed by a hellhound under his control. With Eileen's death, the family was left extinct.
In 2019, Eileen reappeared as a ghost, having been dragged to Hell by the hellhound that killed her. Released from Hell when God opened the Rupture to Hell, Eileen sought the Winchesters help in getting into Heaven which they had learned from the demon Belphegor was impossible for a soul that had been condemned to Hell. Instead, while searching through Rowena's journals for information on how to create a Soul Catcher to contain Eileen's soul, Sam found a resurrection spell created by witch Rowena MacLeod that could bring Eileen back to life. After Eileen helped the Winchesters deal with a family of evil witches, Sam was able to resurrect her.
- Edward Durbin II (deceased) - Men of Letters representative sent as part of a delegation to Europe in 1939. Father of Maura Leahy. Presumably killed by Abaddon in the Men of Letters Massacre of 1958.
- Padraic Leahy (deceased) - Patriarch of the family until 1986. Suffered a nervous breakdown after losing his job. Fell victim to a malevolent Banshee.
- Maura Leahy (deceased) - Daughter of Edward Durbin II and a Legacy as a result. Was not a Woman of Letters or a hunter but rather a lawyer. Retained a basic awareness of the supernatural and knew how to cast some basic spells. Sacrificed herself to banish a malevolent Banshee that had targeted her family.
- Eileen Leahy - Daughter of Padraic and Maura Leahy. As a baby survived an attack by a malevolent Banshee that killed her parents. Rendered deaf by the Banshee attack and was raised by hunter Lillian O'Grady as a hunter herself. Got revenge on the Banshee that killed her parents in 2016 with the help of Sam and Dean Winchester and Mildred Baker. Aided the Winchesters in hunting the Prince of Hell Dagon but accidentally killed British Men of Letters operative Renny Rawlings in the process. Killed by a hellhound controlled by Arthur Ketch in retaliation. Soul dragged to Hell by the hellhound, but released when God opened the Rupture to Hell. Resurrected by Sam using a spell created by witch Rowena MacLeod.
- Lillian O'Grady (deceased) - Raised and trained Eileen following her parents death. Died of cancer when Eileen was sixteen.
- Sam and Dean Winchester - Aided Eileen in getting revenge on the Banshee that killed Padraic and Maura Leahy. Enlisted her help in hunting Kelly Kline and the Prince of Hell Dagon. Resurrected Eileen in 2019.
- Mildred Baker - Befriended Eileen and aided her in killing the Banshee that killed Padraic and Maura Leahy.
- Mick Davies (deceased) - Worked with the Winchesters and Eileen in hunting Kelly Kline and Dagon. Let Eileen go after she accidentally killed British Men of Letters operative Renny Rawlings. He was executed by Arthur Ketch as a result.
- Monsters - As a hunter, Eileen came up against many monsters.
- Banshees - As a hunter, Eileen came up against several Banshees.
- Demons - As a hunter, Eileen has come up against demons at least once.
- British Men of Letters - As a result of Eileen accidentally killing operative Renny Rawlings, the British Men of Letters began targeting her.
- Witches - As a ghost, Eileen aided the Winchesters against the Witch Mother, Emily and Jacinda.
- Three generations of this family was killed by a non-human.