Siryn

Theresa Maeve Rourke Cassidy, also known as Siryn, (voiced by Kelly Macdonald) is a fictional comic book superhero appearing in books published by Marvel Comics, usually those belonging to the X-Men family of titles. She's the daughter of Sean Cassidy, a.k.a. Banshee who first used the alias.

Like her father, the X-Men's Banshee, Theresa is an Irish mutant who possesses a "sonic scream" capable of incapacitating and injuring an opponent's hearing and sending powerful vibrations through the air. She can use these vibrations to fly. Her name refers to the Sirens of Greek mythology.

Theresa was raised by Banshee’s cousin and nemesis Black Tom Cassidy without Banshee's knowledge. By her early teens, she left Black Tom and eventually joined the X-Men offshoots X-Force and later X-Factor.