What is the real name of the X-Man known as Banshee?

The real name of the X-Man known as Banshee is Sean Cassidy. He is an Irish mutant whose powerful sonic cry can stun opponents, shatter objects and create enough lift for him to fly.

Banshee was created by writer Roy Thomas and artist Werner Roth, making his Marvel Comics debut in The X-Men #28 in 1967. Before joining the X-Men, Cassidy worked as an Interpol agent and became involved in conflicts with other criminals and mutants. His codename comes from the banshee of Irish folklore, a spirit associated with a piercing, mournful scream.

Sean Cassidy is often confused with his daughter, Theresa Cassidy, who later uses the codename Siryn and possesses similar sonic abilities. Banshee has also appeared in animated series, video games and the live-action film X-Men: First Class, where he is played by Caleb Landry Jones. Despite these adaptations, Sean Cassidy remains the canonical identity of the original Banshee.