Firebrand
Vulcanologist Danielle Reiley was investigating a volcano in Hawaii when she discovered a scheme by Per Degaton. Running away, she was hit by a weird mystic aura, then fell into a vat of lava. Of course she survived and gained the power to create and control fire.
While recovering from that, she discovered that her brother Rod was the heroic masked vigilante Firebrand. Danielle borrowed one of his costumes and became the new Firebrand. She became a member of the wartime supergroup All-Star Squadron, where she met her future husband, the Shining Knight. Years later she was killed by the villainous Dragon King.