The Squadron Supreme was originally created by Marvel Comics in 1971 as enemies to the Avengers. Originally they were: are Hyperion, Nighthawk, Doctor Spectrum, Power Princess, and the Whizzer... in this episode, Power Princess and Whizzer were renamed Zarda and Speed Demon. The original group was created by comic legends Roy Thomas and John Buscema as a parody of the Justice League, published by Marvel's rival, DC Comics. (i.e. Hyperion-Superman, Nighthawk-Batman, Doctor Spectrum-Green Lantern, Zarda-Wonder Woman, and Speed Demon-Flash).
Spectrum is based on DC's Green Lantern. In this show, Spectrum is voiced by Phil Lamar, who voiced the Green Lantern in the Justice League animated series.
In the comics, the Dark Avengers are a team comprised of multiple villains in the Marvel Universe such as Norman Osbourne, Venom and Bullseye. In the show, they are alternate versions of the Avengers.
Jason Spisak, who plays Speed Demon, played another "speed demon", Kid Flash, on DC's Young Justice (2010).