XANAX was once the mailed fist of the interdimensional being known as XOXOX. Both hail from the same parallel continuum known as Dimension-X. The two travel from universe to universe, draining the emotions of the inhabitants of each before moving on, leaving nothing but soulless slaves in their wake.

XANAX served his master with super-strength, flight, super-speed, pyrokinesis, cryokinesis, and invulnerability, for not only do XANAX's powers mirror the Guardian's in every way, they come from the same extra-dimensional source.

XOXOX and XANAX's arrival on Earth in the 1960's was foretold to the Guardian years earlier. Guardian had time to assemble and train the galaxy's mightiest heroes to stand up to the dire threat posed to the entire universe. Ultimately, XOXOX was defeated by the counter-culture hero known as the Flower Child, who was able to use her mind-altering powers to convince XOXOX to instead spread love and joy through out the multi-verse.

XANAX, however, was defeated by the Guardian and imprisoned in ice on the planet Pluto. There he remains to this day. The planet is quarrantined by intergalactic agreement. It is feared that any energy that might raise the temperature of XANAX's tomb above absolute zero might be enough to awaken what might still be the greatest threat Earth has ever faced.