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Quote1 Ye'd best cover yer ears, kids... this is goin' to hurt some! Quote2

Sean Cassidy comes from an ancient Irish lineage that predates historical records.[13] A former Interpol agent,[14] and NYPD police officer,[15] Banshee, as he came to be known, possesses the mutant ability to generate "sonic screams", capable of harming human auditory systems and even breaking through inch-thick steel.[1] After the tragic death of his wife, Cassidy turned to crime and got involved with the villainous organization Factor Three. This path led him to encounter the mutant superheroes known as the X-Men, and, with their help, he returned to the right side of the law.[1][16][17]

As an ally of the X-Men, Banshee had countless adventures, joining them when most of the original roster quit.[18] In collaboration with the X-Men, he became the partner of Dr. Moira MacTaggert,[19] reconnected with his lost daughter Siryn,[20] and became a mentor for the next generation of young mutants.[21] Unfortunately, the apparent death of Moira turned him bitter[22] and led him to embrace extremist approaches.[23] Still, in the end, he experienced a noble death, giving his life as a last effort to save an airplane full of innocents.[2]

In death, Banshee found no peace, being revived multiple times as a consequence of evil plots.[3][5][7][8] Finally restored to his joyous self on the nation of Krakoa,[24] Banshee was betrayed by Moira, being subjected to a harrowing experience.[10] Traumatized, he was used as a pawn by Mother Righteous in her plan to become a Dominion before the other three clones created by the original Nathaniel Essex, but has since been seemingly freed from her influence.[12]


Early Years[]

Sean Cassidy was born as the heir to the castle and estate of Cassidy Keep, Ireland, as well as a small fortune. He studied at Trinity College, Dublin, where he graduated with a Bachelor of Science.[25]

While hitchhiking one night, Sean drew the ire of a couple of policemen, who tried to arrest him without any charges. Seeing the situation from afar on her motorcycle, Maeve Rourke intervened to rescue the young Sean. After a long pursuit by three police cars, they managed to hit one of the tires and Maeve and Sean fell off a cliff. Sean, however, revealed himself to be a mutant and flew Maeve to safety.[26]

Over the years, both Sean and his cousin, Tom Cassidy, who was also a mutant, competed for Maeve's love, but Maeve eventually chose Sean.[16] The young couple married on a spring afternoon in County Mayo. The band played Night in Soho and Stand by Your Man. They danced until dawn.[27]

Sean began working for Interpol, eventually rising to the rank of inspector. Sean was sent on a special mission, deep undercover. He became separated from Maeve for months with no way to contact her.[16][27]

When he left on the mission, Maeve was in her first month of pregnancy, although Sean didn't know it at the time. Their daughter, Theresa, was born during Sean's absence. Shortly after Theresa's birth, 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 in a terrorist bombing along with a number of other people. Tom Cassidy got custody of the baby and raised her as his own, hiding the truth from Sean as well as Theresa for decades.[20][16][27]

On returning from his mission, Sean was informed that his wife was dead. 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, found himself engaged in some criminal activities.[17]

Sean Cassidy (Earth-616) from X-Men Vol 1 28 001

Under Factor Three's influence

Factor Three[]

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, who 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.[citation needed] Factor Three placed a headband containing explosives 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. Banshee thus felt forced to obey Factor Three's commands and accompanied by the Ogre, performed various criminal missions for the organization.[1]

While in New York City on a mission for Factor Three, 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 Banshee's headband which prevented the detonation mechanism from functioning so that the Banshee could remove it. Once freed of the headband, Banshee told the X-Men all that he knew about Factor Three.[1] Banshee discovered Factor Three's secret European headquarters, only to be recaptured. He participated in the X-Men's battle with the Mutant Master and it was his powers which exposed the Mutant Master as an extraterrestrial.[28]


Sean Cassidy (Earth-616) and Moira MacTaggert (Earth-616) from X-Men Vol 1 96 001

Meeting Moira MacTaggert

Banshee returned to an honest life and time passed without major incident for him, except for his brief captivity at the hands of the Sentinels, and by the second Secret Empire. Professor Xavier later invited Banshee to join the X-Men, when he was recruiting new members to battle the menace of Krakoa.[18] After most of the original team left, Cassidy, along with fellow new recruits Colossus, Nightcrawler, Storm, Wolverine, and Thunderbird, stayed as members of the new X-Men. The second group of X-Men were mostly adults and required no tutoring from Professor X, but trained in the use of their powers, in the Danger Room.[29] It was during this time that he met Prof. Xavier's silent partner, the Scottish geneticist Dr. Moira MacTaggert.[19]

Sean was among those captured by Steven Lang's Sentinels and taken aboard Lang's space station.[30] After a trip to Cassidy Keep, they battled Juggernaut and Black Tom.[31]

Sean Cassidy (Earth-616) from 1994 Ultra X-Men (Trading Cards) 001

During a picnic, they briefly battled Weapon Alpha, who accidentally wounded Dr. MacTaggert and enraged Sean.[32] Cassidy and Dr. MacTaggert soon fell in love, but while Cassidy was based at Prof. Xavier's mansion, Dr. MacTaggert was based at her Mutant Research Center on Muir Island off the coast of Scotland.[citation needed]

In Agarashima, Japan they battled Moses Magnum, a criminal mastermind who had been endowed with the psionic power to cause earthquakes. Magnum unleashed tremendous psionic energy in an attempt to create seismic waves great enough to cause a chain reaction that would destroy Japan. Banshee, simultaneously, used his powers to create waves of vibratory force that would cancel out the waves of force that Magnum was creating. Banshee succeeded, to the extent that only small uninhabited islands in the vicinity of Magnum's base were destroyed. However, the tremendous strain that Banshee had placed upon his powers in performing this heroic feat seriously damaged his vocal cords. Cassidy soon regained his ability to speak, but his superhuman sonic powers, which were dependent on his vocal cords, appeared to have been destroyed.[33]

Cassidy accompanied the X-Men to Muir Island where they battled the menace of Proteus, Dr. Moira MacTaggert's mutant son, who at one point took his mother prisoner. Proteus was defeated and the experience of seeing the woman he loved in danger made Cassidy realize that he wanted to stay by her side.[34] Therefore, Cassidy retired from the X-Men and he and Dr. Moira MacTaggert divided their time between Cassidy Keep and Muir Island. Cassidy briefly returned to aid the X-Men against operatives of Arcade, during an emergency situation when Miss Locke kidnapped Dr. MacTaggert and most of the X-Men were simultaneously engaged in conflict with an android which Doctor Doom had created in his own image.[35]

Later, the X-Men battled Black Tom Cassidy, his partner, the Juggernaut, and Theresa, who had developed sonic powers of her own, which she used under the alias of Siryn. Theresa felt obliged by her duty toward Black Tom, the man who had raised her (and whom she called "uncle" out of respect, although they were actually cousins), to assist him in his crimes.[36][17] After they were defeated by the X-Men, Black Tom gave Theresa a letter to Sean, explaining that she was his daughter. Sean and Theresa were joyfully united at Xavier's mansion.[20]

Generation X[]

Generation X Vol 1 45 Textless

Hard times with Emma

After rejoining the X-Men as an active member, Banshee suddenly realized the Phalanx's kidnapping of the X-Men. He and Emma Frost worked to save some young mutants targeted by the Phalanx. Banshee later became the co-headmaster of the Massachusetts branch of the Xavier institute along with Emma Frost, the branch that housed Generation X.[37][38]

He taught the kids a great deal of things and considered them his children.[39][40] He helped them against countless foes, with them returning the favor on a few accounts as well.[41][42]

One of people they went up against was his cousin, Black Tom Cassidy. During his attack on the school, he took control of Emma's body to hit Sean, hoping to force him to kill her. Knowing that Black Tom wouldn't stop until one of them was dead and that Sean couldn't bring himself to kill her, Emma took control of Sean's mind and sent a powerful sonic scream in her direction, apparently ending her life.[43][44]

After Penance defeated Black Tom, Sean mourned Emma while looking for the missing students. After countless failed attempts, Sean was starting to get desperate, but Emma appeared from behind and jumped into his arms, revealing she had forced him to use the specific frequency that would simply stun her for an hour.[45]

After a joyful reunion, they were approached by Emplate, who offered the kids' location in exchange for Penance. Sean immediately turned the offer down, but Emma contacted him telepathically to convince him of trying to trick Emplate. Sean still thought it was too much of a risk however, so Emma had to knock him out and try to proceed with the deal by herself. Yet, before handing over their ward, Banshee woke up and rescued Penance, before fleeing with her.[46]

It all turned out fine in the end, as all the kids made their way back to the school, but it took some time for Sean and Emma to see eye to eye again.[47]

Generation X disbanded when Chamber was invited to the X-Men, shortly after the death of Moira MacTaggert, which left Sean devastated. He would remain unaware for years that Moira had in fact faked her death, and was still alive.[42][22][48]

Uncanny X-Men Vol 1 403 Textless

With X-Corp


Sean became inactive, until he turned back to his alcoholism for a brief period, and then his bitterness towards the mutants who were like those who supposedly killed Moira got to him. Keen on making up for past mistakes, Sean founded X-Corps, a superhuman militia organization that used primarily mind-controlled former terrorist mutants to protect mutant kind at large. Despite his best intentions, things wouldn't work, and Mystique, who had infiltrated the organization in disguise, slit Cassidy's throat and left him to bleed to death. Luckily, he managed to capture Mystique by releasing Abyss, a mutant who could open an other-dimensional portal and was then taken to the hospital by his former Generation X students.[22][49]


With time, Sean’s throat healed enough for him to regain speech, but he could no longer use his mutant powers. After M-Day, he was asked by the X-Men to go to Muir Island and look for any notes that might help find Professor X. Sean uncovered some startling information, and quickly arranged a flight to Westchester.[50]

Sean Cassidy (Earth-616) from X-Men Deadly Genesis Vol 1 2 001

Banshee's death

He was supposed to meet Nightcrawler and Wolverine but noticed that the Blackbird seemed to be heading towards his plane on a collision course. He quickly used what little power he had to fly and attempted to use his sonic scream to stop the plane from hurting the passengers. Sadly, it was not enough to stop the Blackbird and it rammed into him as well as the plane filled with innocent passengers.[2]

Banshee's body was later found by Kurt and Logan. When the X-Men were blamed for the situation early on, Emma Frost told O.N.E. that the attack had also killed one of the X-Men's best friends.[51]

Cyclops delivered the news of Banshee's death to his daughter, Siryn. Siryn was given a video tape that Banshee had made for the purpose of delivering a message to his daughter when he died. In the message, Banshee stated that he felt he had done more good than bad in his life, and that he hoped St. Peter would allow him entrance into Heaven. He expressed the hope that he would there be reunited with Siryn's mother. Siryn refused to believe that Banshee was really dead, citing all of the X-Men in the past who have been presumed dead but later returned. Sean willed Siryn Cassidy Keep, as well as his pipe.[52]

He was buried at the Xavier Institute, alongside the empty graves of Sway and Petra Kristensen.[53]


Banshee was seen in Erebus by Hercules along with many other deceased beings, gambling for his soul.[54]

Later, Banshee, along with many other deceased mutants, was resurrected by Selene and Eli Bard with the Transmode Virus. He fought against her control to warn Emma and Scott, but it was too strong and he was subdued again.[3] When Selene’s plans fell through, Banshee returned to the land of the dead, until the Chaos King waged war on reality and the gates to the Underworld were opened, allowing Banshee and many other deceased heroes to return. Banshee along with his fellow resurrected X-Men Thunderbird, Esme and Sophie Cuckoo, "Moira MacTaggert" (actually a Shi'ar golem in disguise), and three Multiple Men dupes fought the forces of the Carrion Crow, a minion of the Chaos King. After succeeding in their mission to repair Earth's ley lines and defeat the Carrion Crow, Sean returned to the realm of the dead with "Moira" in his arms.[55]

Uncanny Avengers Vol 1 13 Textless

Banshee fights Captain America, Wasp, and Havok

Horseman of Death[]

Banshee was brought back to life by the Apocalypse Twins, using both the Life and Death Seeds, in order to serve, alongside Sentry, Grim Reaper, and Daken, as one of their Horsemen of Death.[7] After the Apocalypse twins were defeated, Banshee ended up in the X-Men's custody as Beast concluded that healing Banshee of the Death Seed energy that made him a Horseman of Death would take years and highly advanced technology.[56]

Road to Recovery[]

Banshee remained in a coma, carefully looked after by Beast, until an attack by the Reavers forced Hank to release him. Still visibly not recovered, Sean remained entirely silent while Hank and Havok looked for other people to join their quest, occasionally joining the fight, if needed.[57]

On their final confrontation with the Reavers, Sean was infected by Skullbuster and the nanotech that was helping him stay in control began malfunctioning. Incapable of containing his sonic screams for long, he released them against Dazzler, who absorbed them and proceeded to defeat an entire army by herself.[58]

Sean Cassidy (Earth-616) from Uncanny X-Men Vol 5 20 001

Banshee back with the X-Men

In the aftermath of the battle, Sean uttered his first full sentence in years and shared his desire to search for a way to solve his problem by himself... Or let nature take its course.[58]

Sean later resurfaced as part of the Mutant Liberation Front along with Hope Summers.[59] After a confrontation with the X-Men and the newest incarnation of the Brotherhood of Mutants, Sean rejoined the X-Men.[60]

When attacking the O*N*E headquarters, he was caught by surprise by a giant golden sentinel and the machine crushed him under its foot. To the surprise of everyone, however, Banshee managed to belt out a final scream which detonated the robot in a horrifying explosion.[8]

The Krakoan Age[]

Sean was presumably resurrected by a group of mutants known as "The Five," finally cured of the Death Seed energy and returned to his joyful self. He started living on the sovereign mutant nation-state of Krakoa, created by Charles Xavier, Magneto, and Moira (who was still keeping her survival a secret). Later, he was seen celebrating the recognition of Krakoa as a sovereign nation by the UN.[9][24]

Sean Cassidy (Earth-616) from Secret X-Men Vol 1 1 002
Banshee and Unus the Untouchable were approached by Apocalypse and tasked with protecting his grandson, the Summoner, across Otherworld to Arakko.[61] The pair was betrayed by the Summoner as soon as they arrived in Otherworld, being attacked by the dark army of Amenth led by the First Horsemen. Unus was captured while a gravely injured Banshee was taken back to Krakoa by the Summoner, who used him to lead Apocalypse into a trap. Banshee was subsequently taken to the Healing Gardens and had his wounds treated. Rachel Summers eventually felt uneasiness coming from Banshee's mind and decided to verify its cause alongside Kid Cable, belatedly discovering the Summoner's deception.[62] Fully recovered from his wounds, Banshee became one of the candidates for a spot in the X-Men during the first Hellfire Gala, but ultimately lost it to Polaris;[63] an event that left him deeply upset.[11]

Following her depowerment at the hands of Mystique and Destiny, Moira finally revealed herself to Sean in an Irish pub, explaining that she had turned against mutantkind and wanted help sneaking into Krakoa. Overwhelmed by her appearance and the revelation of her mutant power, Sean wanted to take things slow and prioritize finding medical assistance for her recent cancer diagnosis. Moira lost her patience trying to convince him and killed him, ripping his skin off to use his mutant signature and enter a Krakoan gate.[10] After being revived by the Five again, Sean was briefly possessed by the "Skinjacker" and used to cover his tracks. Nightcrawler later took Sean to the Altar, hoping it could help him overcome all the trauma he had recently endured.[11]

Sean Cassidy (Moira VII.1) and Spirit of Variance (Moira VII

Vox Ignis

Vulnerable, Banshee fell prey to Mother Righteous, making a deal with her that got him merged with the Spirit of Variance.[64] The two operated as Vox Ignis under Mother Righteous for a thousand of years in a timeline ruined by Mister Sinister before it was reset. In the aborted future, Mother Righteous used the Spirit of Variance as fuel for a spell that sent the chronicled history of that reality to her past self. As a result, the Spirit of Variance was retroactively erased from existence and Banshee consequently never became Vox Ignis on Earth-616. This alteration to the timeline affected Banshee, prompting him to look for Legion's help at the Altar. Legion finding a vestigial memory of Mother Righteous inside Banshee's mind set off a series of events that culminated in a direct confrontation between her and the Legionaries. In the outcome, Banshee and most of the other Legionaries were killed, and Legion vanished with Blindfold. Before disappearing, Legion seemingly erased the recent traumatic memories of Banshee from his backups, leading him to be resurrected without the weight of such trauma.[12]


Power Grid[66]
:Category:Power Grid/Fighting Skills/Experienced Fighter:Category:Power Grid/Energy Projection/Single Type: Long Range:Category:Power Grid/Durability/Enhanced:Category:Power Grid/Speed/Speed of Sound:Category:Power Grid/Strength/Normal:Category:Power Grid/Intelligence/Learned


Banshee is a mutant who possesses unusually strong sonic abilities.

  • Acoustikinesis: He creates 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.
    • Sonic Scream: He has the ability to shatter solid objects with an incredibly loud and destructive sonic scream.
    • Flight: He has the ability to fly at subsonic speeds by using his voice to propel him through the air and ride via sound waves.
    • Sonar: He could use his sonic powers as a form of sonar (Sound Navigation and Ranging). By sending out a precise, pure note and listening to the returning, altered wavefront of the note, he could evaluate his surroundings in total darkness with varying degrees of resolution.
    • Sonic Shield: He could tighten sound waves around himself or others near him, making a barrier against outside attack.
    • Vocal Disorientation: He has the ability to change someone’s balance, by affecting their equilibrium using his sonic scream.
    • Vocal Trance: He has the ability to subtly influence people's subconscious mind by changing the tones and vibrations of his voice using hypersonic suggestions and persuasive abilities.
    • Vocal Unconsciousness: He has the ability to affect the fluid in someone’s ear causing the person to go unconscious.
    • Sound Immunity: Banshee's hearing and equilibrium were unaffected by his hypersonic abilities or other similar sound/sonic-based abilities.
    • Superhuman Vocal Stamina: He possesses superhuman stamina in his lungs, throat, and vocal cords.


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.


His vocal cords were susceptible to injury from excessive strain in using sonic powers. He had also survived normally fatal throat wounds at the cost of his sonic powers temporarily.



Banshee's Wings: Professor X developed a harness for Banshee's X-Uniform. Using the Harness and his sonic scream he is able to glide on air currents. Using the harness he is able to fly at subsonic speeds.


Conventional firearms, explosive "micro-bombs".


Flight under his own power; X-Men Blackbird, X-Men Stratojet, Professor Xavier's Rolls Royce.



  • When originally created, Roy Thomas and Werner Roth had the Banshee as a female, but Stan Lee told them that female villains were not as popular as male, and she was changed into a male. Roy noted that the way Siryn looked is what Banshee was originally going to look like.
  • Banshee was also immune to his cousin Black Tom's energy blasts.

See Also

Links and References


  1. 1.0 1.1 1.2 1.3 1.4 X-Men #28
  2. 2.0 2.1 2.2 X-Men: Deadly Genesis #2
  3. 3.0 3.1 3.2 X-Force (Vol. 3) #21
  4. X-Force (Vol. 3) #25
  5. 5.0 5.1 Chaos War: X-Men #1
  6. Chaos War: X-Men #2
  7. 7.0 7.1 7.2 Uncanny Avengers #9
  8. 8.0 8.1 8.2 Uncanny X-Men (Vol. 5) #21
  9. 9.0 9.1 House of X #1
  10. 10.0 10.1 10.2 X Deaths of Wolverine #4
  11. 11.0 11.1 11.2 Legion of X #2
  12. 12.0 12.1 12.2 12.3 X-Men: Before The Fall - Sons of X #1
  13. All-New Official Handbook of the Marvel Universe A to Z #1
  14. X-Men #101
  15. Generation X #-1
  16. 16.0 16.1 16.2 16.3 X-Force #31
  17. 17.0 17.1 17.2 X-Force #91
  18. 18.0 18.1 Giant-Size X-Men #1
  19. 19.0 19.1 X-Men #96
  20. 20.0 20.1 20.2 Uncanny X-Men #148
  21. Generation X #1
  22. 22.0 22.1 22.2 Generation X #75
  23. Uncanny X-Men #401
  24. 24.0 24.1 House of X #6
  25. Official Handbook of the Marvel Universe (Vol. 2) #2
  26. Classic X-Men #16
  27. 27.0 27.1 27.2 Uncanny X-Men: First Class #3
  28. X-Men #3538
  29. X-Men #94
  30. X-Men #98
  31. Marvel Team-Up #150
  32. X-Men #109
  33. X-Men #118119
  34. X-Men #127129
  35. Uncanny X-Men #145148
  36. Spider-Woman #3738
  37. X-Men (Vol. 2) #3637
  38. Uncanny X-Men #316318
  39. Generation X #63
  40. Generation X #7275
  41. Generation X #51
  42. 42.0 42.1 Generation X #73
  43. Generation X #25
  44. Generation X #61
  45. Generation X #26
  46. Generation X #2631
  47. Generation X #3234
  48. Powers of X #6
  49. Uncanny X-Men #401406
  50. X-Men: Deadly Genesis #1
  51. X-Men: Deadly Genesis #3
  52. X-Factor (Vol. 3) #7
  53. X-Men: Deadly Genesis #6
  54. Incredible Hercules #129
  55. Chaos War: X-Men #12
  56. Uncanny Avengers #22
  57. Astonishing X-Men (Vol. 4) #1316
  58. 58.0 58.1 Astonishing X-Men (Vol. 4) #17
  59. Uncanny X-Men (Vol. 5) #15
  60. Uncanny X-Men (Vol. 5) #16
  61. X-Men (Vol. 5) #12
  62. X of Swords: Creation #1
  63. X-Men Vote Comic Strips #5
  64. Legion of X #23
  65. Official Handbook of the Marvel Universe A to Z #1
  66. Official Handbook of the Marvel Universe A to Z Vol 1 1