ALIAS: Banshee
REAL NAME: Sean Cassidy
NATIONALITY: Cassidy Keep, Ireland
TEAM AFFILIATION: Generation X. Former member of X-Men
AGE: Possibly late 30's, early 40's
POWER: Ability to produce a sonic scream along with psionic abilities. Ability to manipulate the sonic scream to produce various effects such as barriers, rendering a person unconscious, flight.
FIRST APPEARANCE: X-Men #28

Sean Cassidy, better known as "Banshee" of Generation X is not new to crime fighting. First shown in X-Men #28, Banshee has a long, detailed past that involves fighting crime and being one who has caused crimes. Sean Cassidy was born as the heir to the castle and estate of Cassidy Keep, Ireland and a small fortune with it. He graduated from Trinity College in Bublin with a degree of Bachelor of Science and quickly became a detective at Interpol (the International law enforcement organization) At this point in his life he met and married Maeve Rourke. Sean's life was falling into place and he lived happily as he rose in the ranks at Interpol and achieved the rank of inspector. Cassidy was content with the way things were working out for him, yet he still had a few problems. He had discovered his mutant ability to project sonic screams when he was a child, yet now he had to keep them secret, from his wife and from Interpol.

The problem lay in that one person, Black Tom Cassidy, knew of his powers. Black Tom (Black as in the "Black Sheep" of the Cassidy Clan) had superhuman powers himself and he was constantly at war with his cousin Sean, mostly for the love of Maeve Rouke. During their marriage, Sean was assigned by Interpol to a top secret mission which required him to stay out of touch with his family for a considerable length of time. When he had left, Maeve was in her first month of pregnancy. Their daughter, whom Maeve named Theresa, was born during his absence. Maeve had later taken Theresa with her on a visit to her relatives in Armagh in Northern Ireland and while there, Maeve was caught in a terrorist attack and was killed. Theresa was never found and therefore assumed deceased as well. The reality was that Black Tom Cassidy had been in the area the day of the terrorist attack. Black Tom secretly carried Theresa off with him in hopes that when she grew older, she would develop powers of her own and aid him in his series of crimes.

Returning home from his mission, Sean was informed of his wife and daughter's fate. Sean Cassidy would not accept it and so he buried himself in work at Interpol. Eventually he left Interpol to become a freelance operative and as time went on, he became engaged in criminal activities. It was never discovered that he was guilty of crimes but the mutant known as the Changeling did. The Changeling, with help from a organization of powerful mutants known as "Factor Three", contacted Sean and invited him to join Factor Three. Sean learned quickly the evil of Factor Three's goals and refused to join. However, the Changeling and his superior, the Mutant Master, set their agents to capture him. They placed a headband of explosives over his head which could be detonated by remote or if he attempted to take it off. To make things that much more difficult, he was also placed under the supervision of a human agent called "the Ogre". Banshee was forced to follow Factor Three's commands and was sent to perform many criminal missions on their behallf. While on a mission in New York (under Factor Three's command) he ended up in a clash with the original X-Men and both he and the Ogre were captured. Professor Charles Xavier used a psionic "mental bolt" on the explosive headband in order to be able to remove it. Now free, Banshee told all he knew of Factor Three to the X-Men. Banshee eventually discovered Factor Three's secret headquarters in Europe, but was captured again by the villainous team. The X-Men fought the Mutant Master and it was Banshee's powers which helped to defeat the team and expose the Mutant Master as an extraterrestrial.

After this incident, Banshee once again settled into a regular, law-abiding life. Years later, Professor Xavier later invited Banshee to join the X-Men as he was recruting new members to battle the "living island" known as Krakoa. With this fight, Banshee stayed with the X-Men and here he met the Scots geneticist, Moira MacTaggert. They fell in love even over their long distance relationship, Sean being at Xavier's mansion in the U.S.A. and Moira at her mutant research center on Muir island of the coast of Scotland. Banshee took part in the missions that lay ahead of the X-Men, but one caused a serious problem for himself. It was at a mission in Japan that halted Sean's life as the Banshee. In Japan, the X-Men found themselves fighting a villain known as "Moses Magnum" who was in attempts to create seismic waves large enough that could destroy Japan. Banshee tried to use his powers to create waves of his own in order to counteract Moses Magnum's. He succeeded to point that only small islands in the area were destroyed, but not without consequenses. With the tremendous strain that Banshee put on himself in order to stop this villain, Banshee did serious damage to his vocal cords and lost his mutant abilities of the sonic scream. His voice returned but without any powers, he decided to leave the X-men and left to stay with Moira MacTaggert on Muir Island.

At a later time, the X-Men came across Black Tom Cassidy, the Juggernaut and Theresa who had developed sonic powers similar to her father's. Going by the codename of "Siryn", she felt dedicated to Black Tom who had raised her, and went along with his crime sprees. After they were defeated, Black Tom gave Theresa a letter to Sean that explained that she was his daughter. They enjoyed their reunion and they both learned of their powers from one another. It seems that in actuality, Siryn has more abilities and flexibility over her sonic scream. Banshee's is the ability to create powerful sonic waves with his voice, often in unison with his limited psionic abilities that only function with his sonic power, which can achieve various effects depending on the pitch. Certain frequencies could cause a person to fall asleep, fall unconscious, or become confused. Altering his sonic powers gives him the ability to fly, to shatter objects and be able to create many different effects such as a sonic shield as seen in GenX Annual '96.

Banshee's powers eventually did return, enabling him to once again fight crime alongside the X-Men. It was when he and the next generation of mutants were attacked by a being known as the Phalanx, did he completly dive back into his role as the Banshee. Fighting to protect the next generation of mutants and freeing them from the bonds of the Phalanx, Banshee and Emma Frost (aka: White Queen) took on the role as teachers in order to help young mutants to learn of their powers and live in a world that hates and fears them. Banshee and White Queen re-opened the Acadamy and there began their lives as Head-Masters to the team of mutants known as Generation X. Banshee was initially worried about how he was going to deal as a teacher, worried they would eat him alive. With Jubilee in the fray, I'd say he does have to worry a bit, but none the less he is doing an excellent job as teacher. Banshee is fairly strict when the kids are misbehaving, but kind and fair, none-the-less. Sean takes well to children and the children feel pretty comfortable around him, unlike with Emma Frost who has a quick temper. It's not unusual to see Sean joining in on a game with the students from time to time, playing volleyball or helping out the students in their training sessions. He is like a protective father to them since he feels the guilt of not being there for Theresa all those years before. He wasn't there for his wife, for his daughter and he's determined not to make any mistakes while the teenagers of Generation X are under his watch. He cares deeply for the children of Generation X and he hopes to help achieve the goal that mutants and humans can live peacefully.