Banshee
Real name: Sean Cassidy
Full name: Sean Cassidy
Aliases: Death
Alter egos: Banshee (FOX), Death Seed Banshee
Creator: Marvel Comics
Alignment: Good
First appearance: X-Men #28 (January, 1967)
Place of birth: Cassidy Keep, Ireland
Occupation: Currently founder and director of operation for X-Corps, formerly Adventurer and Headmaster at the Massachusetts Academy, in charge of Generation X, Interpol Inspector and Agent, freelance detective, professional criminal, involuntary operative for Factor
Base: Muir Island, off the coast of Scotland. formerly Massachusetts Academy; Xavier Institute
Teams: X-Corps, Generation X, Cerebro's X-Men, Apocalypse's Horsemen, X-Men, Factor Three
Relatives: Maeve Rourke Cassidy (wife, deceased), Thomas (Black Tom, cousin), Theresa Rourke (Siryn, daughter)
Gender: Male
Race: Human
Height: 6'0 • 183 cm
Weight: 170 lb • 77 kg
Eye color: Green
Hair color: Strawberry Blond
Superpowers: Audio Control, Enhanced Hearing, Flight, Force Fields, Sonar, Sonic Scream
Stats: intelligence 75, strength 10, speed 60, durability 40, power 65, combat 70

History:
Sean Cassidy was born as the heir to the castle and estate of Cassidy Keep, Ireland, as well as a small fortune. After graduating from Trinity College, Dublin, with the degree of Bachelor of Science, Cassidy became a detective at Interpol, the international law enforcement organization. By the time he married Maeve Rourke, Cassidy had risen to the rank of Inspector at Interpol. Although Cassidy had discovered his mutant powers in his adolescence, he kept them secret, even from the rest of Interpol. However, Cassidy's powers were known to his disreputable cousin Black Tom Cassidy, who had discovered that he himself was a superhumanly powerful mutant. Sean and Black Tom had long been rivals, especially over the love of Maeve Rourke, before she ultimately married Sean. Sean Cassidy was assigned by Interpol to a top secret mission which required that he stay out of touch with his family for a considerable amount of time. When he left on the mission, Maeve was in her first month of pregnancy, although neither Tom nor Maeve knew it at the time. Their daughter, Theresa, was born during Sean's absence. Maeve took the infant Theresa with her on a visit to her relatives in Armagh in Northern Ireland. While she was there, Maeve, an innocent bystander, was killed by an explosion caused by terrorists. No trace of Theresa was found by the authorities, and they and Maeve's relatives assumed that Theresa had also been killed in the explosion. In fact, however, Black Tom Cassidy had been present at the scene of the explosion and had secretly carried Theresa off with him. Black Tom suspected that Theresa might develop superhuman mutant powers as she grew older, and therefore he intended to raise her secretly so that he might exploit her powers himself. On returning from his mission, Sean Cassidy was informed that his wife was dead. Those who knew that Theresa had been born decided not to inform Sean Cassidy that Maeve had had a daughter in order to spare him further grief. At first Cassidy attempted to escape his despair over this news by throwing himself into his work at Interpol. Eventually, however, the still melancholy Cassidy left Interpol to become a freelance operative, and as time went on, he found himself engaged in criminal activities. The legal authorities never discovered that Cassidy was guilty of crimes, but the mutant known as the Changeling did, thanks to the technology of the subversive organization of superhumanly powerful mutants and their underlings known as Factor Three. The Changeling contacted Cassidy, whom Factor Three's technology had also identified as a superhumanly powerful mutant, and invited him to join the organization. Cassidy was appalled upon learning of Factor Three's goals and adamantly refused. However, the Changeling and his superior, the so-called Mutant Master, agreed that Cassidy's powers and knowledge of the workings of law enforcement agencies were too valuable for Factor Three to lose, and so they sent their agents to capture Cassidy. Factor Three had a headband containing explosives placed around Cassidy's head. If Cassidy defied their orders, the headband could be detonated by remote control; it would also detonate if Cassidy attempted to remove the headband himself. Furthermore, Factor Three put Cassidy, who went by the code name of Banshee, under the supervision of one of their trusted human agents, the Ogre. The Banshee thus felt forced to obey Factor Three's commands, and, accompanied by the Ogre, performed various criminal missions for the organization. While in New York City on a mission for Factor Three, the Banshee clashed with the original X-Men, who captured both him and the Ogre. The X-Men's leader, Professor Charles Xavier, used a psionic 'mental bolt' on the Banshee's headband which prevented the detonation mechanism from functioning so that the Banshee could remove it. Once freed of the headband, the Banshee told the X-Men all that he knew about Factor Three. Later, the Banshee discovered Factor Three's secret European headquarters, only to be recaptured. But the Banshee participated in the X-Men's battle with the Mutant Master, and it was the Banshee's powers which exposed the Mutant Master as an extraterrestrial.

Powers:
 Banshee is a mutant who possesses unusually strong sonic abilities.    He created powerful sonic waves with his voice with which he could achieve various effects, often with the assistance of psionic abilities which function only in unison with his sonic abilities.               A gifted detective, seasoned undercover operative, and unarmed combatant, Sean was also well-versed in combat strategy and tactics. He was an excellent marksman, amateur machine-smith, educator, organizer and lobbyist. His interests included American country music and playing the piano.