Banshee (Marvel Legends)
"Unlike most members of the X-Men, Sean Cassidy had a lifetime of experience behind him when he joined the group. Raised on his family estate in Ireland alongside his cousin ""Black Tom"" Cassidy, Sean grew up with a strict sense of right and wrong, and a hardheaded sense of practicality. This upbringing led him to a career in law enforcement, and eventually to the ranks of Charles Xavier's group of heroes. His history with the X-Men has been rocky - a tale of equal parts triumph and tragedy. Though he became close friends with Xavier, and nominal second in command of the team, repeated injuries led him away from the super hero lifestyle. Fate, however, had other plans. Banshee gave his life using the last bit of his power in an attempt to save a doomed flight full of innocent civilians. Includes the wing of Annihilus."