Demian Anikanov was once the best friend of Alexei Krylenkov (aka Steel Wolf), and participated with him in the experiments that granted Alexei his powers. Unfortunately, that same process killed Demian.
However, after years of his body soaking up the residual radiation of the others who died in that selfsame procedure (having all been buried in a single mass grave), a flicker of life re-awakened him. The villain Fulcrum detected this energy signature, and recovered what little remained of Demian’s body, merging it with a massive suit of powered armor, giving birth to the walking atomic monster that now called itself Warhead.
For years, Demian’s memories remained buried, until a battle with Steel Wolf re-awakened them. Enraged by the fact that his former friend had not only survived, but thrived, as a result of the experiments performed on them both, Demian swore vengeance on Steel Wolf, and has vowed to destroy everything he holds dear.