Cassandra Lang (Earth-1543)

Origins
As a young child, Cassie suffered from a congenital heart defect. To save her life, her father, Scott Lang, stole Henry Pym's Ant-Man equipment and Pym Particles, which he uses to rescue Doctor Sondheim, the only doctor able to cure Cassie's condition, from Cross Technological Enterprises.

As Cassie became older she wanted to become a hero just like her father. With Ant-Man for a dad, Cassie was able to encounter the world's greatest heroes on a frequent basis. Scott's time as an engineer for the Fantastic Four brought Cassie to the team's then headquarters of Four Freedom's Plaza. After the divorce of her parents, Cassie's father joined the Avengers. Cassie spent much of her time with her father living in Avengers Mansion. She loved and admired her father, and formed strong relationship with his colleagues (she even referred to Tony Stark as "Uncle Tony").[4] Unbeknownst to anyone, Cassie used this time to secretly expose herself to Pym Particles, in hopes that she could be a superhero like her father.