Sean Cassidy
Portrayed By
Colin Farrell

A loner who keeps to himself while working through Manhattan, attempting to keep what once resembled law & order.


  • Birthday: December 16, 1980
  • Position: Ex-Lawman
  • Fame: He's known for keeping the peace (somewhat) in Manhattan. He'll escort mutants to Rykers, and do what he can to stop the gang fighting.
  • Family: None

For the early years of their lives, Sean and Tom Cassidy were like brothers, and they found at an early age that not only were they both mutants, but they were immune to each others' powers. The two remained close as they grew up, even when Sean went into law enforcement, eventually secretly becoming an undercover Interpol agent. Only one thing came between them; a stunning blonde with a penchant for motorcycles by the name of Maeve Rourke.

Sean met Maeve when she rescued him from two corrupt police officers who were intent on framing the young man as an IRA scout (he was simply hitchhiking home from a concert). Despite having just met the girl, Sean used his powers openly in front of her. To his surprise, she wasn't the least bit frightened by them.

He brought her home to Cassidy Keep, and though he wasn't as charming as he wished he'd be, he won Maeve's heart and after a time the two were married.

Shortly after their wedding, Sean had to go deep undercover for Interpol, unable to have any contact outside of the mission. Unbeknownst to him, Maeve was pregnant with their daughter, Theresa. She gave birth to the little girl while Sean was still incommunicado, and the news that he was a father was unable to reach him. Sean was, in fact, so deep undercover that not even the news of Maeve's death could reach him until he came home. She had been visiting family in Belfast when an IRA bombing had taken place, killing her. It was assumed by most that little Theresa had perished as well.

When Sean had returned home, he was crushed with grief and guilt for not being there to prevent the deaths from happening. Sean threw himself into his work with Interpol, opting not to return to Cassidy Keep due to the memories it held. He worked for Interpol (and for a good while, the NYPD as a liaison) for 10 years until he was forced to quit after a botched mission in which a mercenary killed the mobster they were trying to find information on (though in doing this, he saved Sean's life, as the criminal was about to shoot.).

With all of this turmoil in his life, Sean fell into a deep depression. What was his point for living? No job to bury himself in. No family to distract him and love him for who he really was and not pretending to be…Nothing… After a night of drinking at a local pub(Irish of course), Sean began his lonely trek home. After some time, he'd decided that his expertise could be used in the States, especially with mutant unrest growing in NYC. So he immigrated to the US, legally, and got himself a job with the NYPD. He quickly rose up through the ranks with his experience and his skills, making detective. Sean was one of the first to come out as a mutant, and gladly registered, even though he had some inner reservations about being kept under the government's thumb. With the anti-mutant sentiment growing, and his brothers on the police force growing cold and angered towards him, Sean thought it was wise to quit, before an incident occurred and someone got hurt.

After the destruction of Manhattan and the rise of anger and violence against mutants, Sean stayed in Manhattan, doing his best to bring his own form of law & order to a chaotic area. He would escort peaceful mutants to Rykers, and he did his best to keep crime down, though he's mostly been unsuccessful.


Flight: Due to Sean's extraordinarily powerful mutant lungs, he has the ability to fly. He can fly unaided at a speed up to around 75 mph. His reach isn't limitless, only being able to go the distance of about 50 miles some form of rest. He can carry someone with him, but that brings both speed and distance down to half, since they'd hardly be aerodynamic, plus he'd half to tone his scream down so as not to damage the other person's ears. As with all of Sean's powers, he can't do a thing if his vocal chords are damaged in some way.

Sonic Scream: Sean's scream is his primary weapon and has the same force as a concussive blast. He can produce up to 150 decibels. Against a person, it would the equivalent of blunt bashing damage, but on top of that he can damage eardrums, like listening to a loud rock concert for too long. He can only do this for short periods of time, as an assault on foes or obstacles, for instance. Also, he needs to see his target and his range is only about 20 yards away. Too much use can cause him to lose his voice temporarily. Longer prolonged use could possibly damage his vocal cords permanently. Sean is also impervious to his own voice, so he cannot damage his ears.

Sonic Shield: Sean can emanate sound waves within the direct vicinity of him, and use them as a reverse-concussive force against most projectiles, in essence using his power as a form of forcefield. When he's not using his sonic powers, he's as vulnerable as any normal person. He's not shielded from psionic powers or blasts of concussive force. If he becomes distracted or disoriented, he can drop his shield. The shield can only be directed to one area, which most of the time would be right in front of him. While he's got the 'shield' up, he cannot use any other power. Continuous hits against the shield weaken it, and Sean. As with all of Sean's powers, he's limited by his vocal chords.

Vocal Chords: If Sean can't make a noise, he's powerless. Put him in a vacuum, cut his throat, or even just knock the wind out of him and he's as helpless as any normal guy (well, any normal well trained ex-espionage agent). If Sean strains his voice by maxing out his powers he can lose his voice for extended periods of time leaving him powerless. Regaining his powers after straining his vocal chords can take up to a week or two much longer than just regaining his voice.


Bartending: Sean's pretty good with the alcohol, both in drinking it and in serving it. He owns his own bar and regularly works, serving the patrons. He'd picked up the art as a hobby at first, in his younger years at the Cassidy Keep. He continued to work at it all through his life, and finally took a course in NYC to get his license.

Charisma: Sean can be quite charming, even though it can come off as being goofy sometimes. He uses his charisma to scare foes, to cheer friends, and to charm ladies. His charisma is natural, and he doesn't feel as sophisticated when around others who work harder at it.

Detective: Sean has made a life for himself as a successful detective, working with both Interpol and the NYPD. He's worked to uncover many criminal organizations around the world. He's been trained to look for clues and is well adept at finding things out.

First Aid: Between work with Interpol and the NYPD, Sean's had to learn quickly how to dress a wound and set bones. He doesn't have extensive experience but he is good enough to patch someone up so they can be transported to better facilities.

Martial Arts: Sean had been trained in unarmed combat from the day he'd entered training with Interpol. He took to it easily enough and trained hard to become the experienced fighter that he is. His skill is at a professional level, enough to keep him alive. There are many out there, however, who could wipe the floor with him. He can be overcome when a group of three or more attack.

Subterfuge: Using his charisma and an exceptional skill of acting and lying, alongside the superior training he received from Interpol, Sean has been succesful in covert ops and in infiltrating criminal organizations. He may be a tad rusty, though, since he hadn't needed to use the skill much since he botched a job with Interpol and was released from service.

Weaponry: Sean began firearms training with Interpol and had grown increasingly accurate and accustomed to their use. He refrains from using deadly force as much as possible, but guns can be used, if skilled enough, in non-deadly ways. He carries weapons on him at all times when he's in civilian attire, but sheds them off once he becomes Banshee. Through his work with the NYPD, he's licensed to carry and keeps up his training and marksmanship rating.

Breath Control: Sean has possibly the largest lung capacity that a man can have. He is capable of holding his breath for minutes but the real application comes in his prolonged screaming. He has also trained himself to be able to time his breathes to keep a near continuous stream of sonic energy going in order to stay in flight or keep up a shield. A single breath, if closely watched, can last for about 2 minutes.

Hearing: Despite the massive amount of loud noise that he is constantly subjected to Sean ears are actually more sensitive than normal. He can hear beyond the normal audible range in both directions. He can perceive changes in tone or the direction of noises much more clearly than others. His hearing is much closer in its range, accuracy and sensitivity to animals than to most men. His ears also are immune to loud noises, he will not suffer hearing loss or pain regardless of how loud a noise is.


Guns: Before Sean became proficient in the use of his powers he relied on more mundane sorts of weapons. Sean still often carries a gun or two, especially if he's working on a case or expecting trouble. Sean prefers handguns though he does own a massive shotgun as well. He has three main pistols that he uses, a Desert Eagle .50, and two twin Glock 35s. When carrying the Glocks he keeps them in dual shoulder holsters but the Desert Eagle is usually found at his hip.

Contacts: Sean who is a former agent of Interpol, as well as a former detective in the NYPD. He has contacts around the world, both legit and otherwise. However, in his current state, seeking them out would prove difficult.

Lord Cassidy: When Sean's parents passed away he became Lord Cassidy, owner of Cassidy Keep and the recipient of the majority of his family's money, assets, etc. Sean's investments and assets bring him in quite a bit of money per year. On top of that Sean owned and ran a bar in midtown Manhattan that did quite well. Sean leaves all the care of his familial home and assets back in Ireland to a trusted family employee.


Drinking: Sean has a love hate relationship with drinking. He loves to drink and hates to stop. Normally Sean keeps a hold on this sort of thing because he knows he has responsibilities. However when faced with a difficult situation he often finds himself slipping into periods of excess. More than once Sean has needed the intervention of friends or another intense stimulus to knock him out of a drinking rut. In the end Sean is aware that it's an issue but it's not one he is willing to face or discuss.

Maeve: Is it really better to have loved and lost? Sean's one true love meant the world to him but he never really sat down and considered what he had. He took Maeve for granted, that she would always be there for him. He knows he failed her, as a husband and in other ways as a protector. He has many regrets over his short marriage to her. Sean is still in no place to start a relationship right now even though it's been years since Maeve's death.

Criminals: Throughout his time with Interpol Sean infiltrated various terrorist and criminal organizations to bring them down. There are those who hold a grudge against Sean for sending either themselves or their associates away to jail. Anyone with enough contacts could conceivably track Sean down to extract revenge against him.

Smoking: On top of drinking Sean also has another vice, nicotine. Originally Sean smoked a pipe, imitating the one his father smoked. Eventually for convenience's sake Sean switched to cigarettes. It's ironic that someone who relies on his lungs and throat so much would risk damaging them like he does.


2016/01/10: Good Night, Sleep Tight banshee jubilee
2016/01/10 - Death From Above banshee ellen hotwire jubilee
2015/12/28 - Chances Are banshee gambit laura

Watch For

  • His ability to drink himself to a stupor.
  • His not hesitating to help someone in distress (damsel or otherwise).
  • His inability to walk away from a fight.


Quotes by or reminiscent of character.


Icon Name Notes


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