Wildfire was originally Drake Burroughs, an astroengineer. While he was working on a new propulsion system, the unit's safety valve snapped and discharged a blast of anti-matter energy. Burroughs was engulfed instantly but somehow his consciousness survived and Burroughs found himself transformed into a being of pure anti-energy. Fortunately, his colleagues had on hand a containment suit that could be used to keep Drake's anti-energy from dispersing. Once confined to a specific area, Drake's energy form stabilized and became self-regenerating.
After many adventures and becoming the Legion leader, Wildfire recruited a young Amerindian mutant, DawnstarIt was clear to their teammates that they were extremely fond of each other, if not actively in love. However, she feared that she would never know physical love since Wildfire did not possess a physical body.
In the post-Crisis continuity, he used his powers to reignite Earth's sun, and eventually his consciousness ended up in Sun Boy's corpse, a condition he maintained until the Legion reboot.
As a kid I thought this character was so cool, the suit, the mask, a real bad ass. Here is my take on this awesome character. Interestingly enough as I grew up, I  became aware we are also made out of energy and we are also luminous beings.