The SHOCKER & SPEED DEMON:
Leila is the wife of the Ringer (Anthony Davis). After Anthony is manipulated by Herman Schultz (The original Shocker) into a life of crime (which included multiple conflicts with Spider-Woman), he is eventually killed by the Shocker after he quits the Sinister Syndicate. Leila swears revenge on all of them.
Sometime later, she allies herself with Boomerang, Rhino, and Quicksand. The group became involved in a massive fight that also involves Schultz, Doctor Octopus, Swarm, the Answer, and Spider-Woman, with each party trying to gain control of a highly experimental gun. During the fight, Davis kills The Shocker. Spider-Woman eventually stood victorious and most of the costumed criminals are taken into custody. Leila escapes with the help of an unlikely ally, Jamie Schultz, The Shocker's wife.
Jamie explained that Herman was a violent man. He was abusive and uncaring. Leila and Jamie bonded over their losses. Jamie showed Leila how Herman was able to harness such destructive forces. Jamie was a mutant, able to accelerate herself past the speed of sound. She would charge his gyro-static conduits. Leila convinced Jamie to reclaim her maiden name, and let her use Jamie's dead husband's gear as they pursued vengence against their enemies. A modern day super powered Thelma and Louise; they are Jamie Sanders, the Speed Demon and Leila Davis, the Shocker.