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Real Name
Siobhán Maeve Cassidy
Current Alias





Seán Cassidy (father), Maeve Rourke Cassidy (mother), Cessily Kincaid (daughter), Black Tom Cassidy (uncle)


Base Of Operations
Xavier Institute




Unusual Features

Irish , British, American

Marital Status

Student (College), adventurer


First appearance




Powers and Abilities


  • Personal Vocal Audiokinesis: Siobhán has the ability to generate huge amounts of sonic energy using her voice. This "sonic scream" can be used to create various sonic effects through the combined action of her vocal cords and limited psionic powers which can only be used in conjunction with the sounds she produces.
  • Omnitone: She has the ability to make sounds in any pitch or tone. Therefore, Banshee has the ability to speak, sing, whisper, yell, hum, etc. in any pitch or tone.
  • Vocal Mimicry: Banshee has the ability to perfectly reproduce any sound that she hears: chainsaws, car engines, fire alarms, rifle-shots, camera shutters, dogs barking, crying babies, music, and other human voices.
  • Sonic Scream: Banshee can cause her vocal cords to vibrate over a wide range of sonic frequencies and produce a volume of sound ranging up to at least 140 decibels. Thus, Banshee has the ability to shatter solid objects with a sonic scream. Siobhán is able to shatter certain materials by using different wavelengths of sound.
  • Sonic Lance: By focusing her sonic vibrations while screaming into an intense beam. This is used as a sort of "battering ram" that can stun or even destroy most solid objects.
  • Razor Wind: Use sound to slice enemies.
  • Reflective Beams: Shoot beams of sound that can bounce off of any surface.
  • Scatter Shot: Fire sound blasts that split into multiple fragments.
  • Sound Bullets: Fire in short sequence over a wide area.
  • Zap: A tiny short release of sound to cause pain or discomfort, usually too low-powered to be destructive.
  • Counter Vibration: this ability allows Banshee to create a counter vibrating frequency to cancel out another object's frequency, thereby destroying it.
  • Flight: Banshee can ride the sound waves produced by the sonic vibrations of her scream, a carrier wave. She is able to fly at the speed of sound (approx. 761 mph at sea level; this speed decreases at higher altitudes).
  • Sonic Pulse: She can use sonic pulses to let her move very fast for short periods of time.
  • Echolocation: By sending out a precise, pure note and listening to the returning, altered wavefront of the note from various objects near her, she can use these echoes to locate and identify the objects in his environment. She can evaluate her surroundings in total darkness with varying degrees of resolution. Alternately, she can use ambient sounds to do the same. Since this ability isn't based on sight, invisibility, camouflage, and purely psionic illusions are useless.
  • Sonar: Echolocation using water as a medium instead of air.
  • Sonic Null Field: She can project a field of silence in a area making no sound reach outside the area or no sound outside the area in.
  • Sonic Amplification: She can amplify sound carrier waves allowing her to hear conversations or noises from far off.
  • Sonic Shield: She can tighten sound waves around herself or others near her, making a barrier against outside attack.
  • Voice Projection: She has the ability to project one's voice great distances or even into a room without being physically present.
  • Ventriloquism: She has the ability to make it seem as if one's voice is projecting from another object.
  • Physical Disruption: Banshee is able to emit sound frequencies that are able to impact bodily functions.
  • Vocal Disorientation: ability to change someone’s balance, by affecting their equilibrium using her sonic scream.
  • Vocal Nausea: She can also cause people to experience nausea and discomfort at certain frequencies.
  • Vocal Blindness: She produces a frequency that causes vibration of the eyeballs, and therefore distortion of vision.
  • Vocal Unconsciousness: She has the ability to affect the fluid in someone’s ear causing the person to go unconscious.
  • Banshee Cry: Banshee will gain the ability to raise her sonic scream to such an intensity that the sound will begin to cause internal brain and other organ damage, eventually to the point of death.
  • Sonic Healing: can use high and low frequency sound waves to vibrate nerve endings in the body to heal wounds.
  • Vocal Trance: She has the ability to subtly influence peoples subconscious mind by changing the tones and vibrations of her voice using sonics, the effects tend towards blatant hypnosis.
  • Emotion Manipulation: She can generate high pitched sonic vibrations that are subtle enough to avoid her being consciously detected by others and, thereby, allowing her to influence the actions of others by causing moods such as happiness, anger, or fear.
  • Love Induction: ability to influence human beings with a certain pitch of her voice, causing them to fall in love with her without regard to gender or sexual orientation.
  • Siren Song: She is capable of emitting an astonishingly beautiful and enchanting song that is capable of luring anyone who hears it to come towards her.
  • Enhanced Physiology: Banshee's body has several adaptions for her sonic powers.
  • Superhuman Vocal Stamina: Her vocal cords are tremendously strong, so that she can produce sonic effects through screaming constantly for hours at a time without noticeably tiring or injuring her vocal apparatus. Banshee’s vocal cords and the interiors of her throat, mouth, and lungs are also superhumanly tough, so that the intense pressures and constrictions that she produces do not cause her any injury. Additionally, her lungs have an increased capacity allowing her to scream for prolonged periods of time, as well as breathe comfortably during flight.
  • Enhanced Hearing: Banshee's ears are able to hear with amazing clarity, distance, and even frequencies outside normal range. She can pick up every single sound, can decipher layer upon layer of differing sounds/conversations, locate the source of noise or pick up a sound from a mile away in a busy city. She can hear a person's heartbeat at a distance of over twenty feet, or people whispering on the other side of a standard soundproofed wall. Through practice, Banshee is able to control her hearing acuity, mentally blocking out specific sounds like her own breathing and heartbeat, all ambient sounds to a normal human level of perception, or all sounds but a particular sound she is concentrating upon.
  • Sonic Sight: the ability to mentally visualize soundwaves in her environment. Using her echolocation ability she can render a 3-D image of her environment.
  • Sound Immunity: Banshee's hearing and equilibrium are unaffected by the effects of her scream and similar abilities.


  • She has a gift for detective skills.
  • She is a seasoned and unarmed combatant, and he is well-versed in combat strategy and tactics.
  • She is an excellent marksman, amateur machinesmith, organizer and lobbyist.
  • Her interests included American country music and playing the piano.

Strength level

Siobhán Cassidy possesses the normal human strength of a woman of her age, height, and weight who engages in moderate regular exercise.


  • Major injuries to his throat leave her temporarily unable to use her sonic powers. Excessive vocal cord strain can also cause her to temporarily lose her powers.
  • Sound requires a medium to travel through, so a vacuum would render her powers useless.


Equipment: None known.
Transportation: None known.
Weapons: None known.


  • For all intents and purposes, Siobhán is the Nexus version of Sean Cassidy (Earth-616). Her father in Earth-515, Seán would be equivalent to Earth-616 Sean's father. Siobhán is also comparable/analogous to Earth-616's Siryn.
  • The name Siobhán is the female version of Seán.
  • Siobhán was born blind. She had to learn to deal with this handicap while growing up; however when her sonic powers developed, she replaced her sight with echolocation. In most cases, she can feign normal sight, and she usually refrains from telling new people about her blindness.


  • No trivia.

See Also

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Links and References

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