Guy Gardner is famous for being one of the first three human members of the Green Lantern Corps introduced in the DC Universe. He's also synonymous with a mop of red hair and an equally fiery temper. Said anger management issues eventually had him relinquish both his Green Lantern ring and his role in the Corps, but this wasn't the end of his ring-slinging days.
Seeking Sinestro's yellow ring, Guy Gardner would eventually have evil beware his power in an entirely new way. With a new ring, a new color and even a new codename, Guy Gardner's identity would dramatically change for the next decade. Here's how Guy Gardner became the only hero to heroically wield a yellow power ring.
The Lord of the Ring
Following his reassignment to Hal Jordan's former role, Guy Gardner grew quite comfortable with being the guardian of Sector 2814. When Jordan returned to retake the position, Gardner angrily rejected him and challenged him to a battle. The rule was that the loser would give up their ring and role in the Green Lantern Corps, with Gardner promptly doing so when he lost. Unfortunately, his attempts at trying to be a hero without a power ring failed, especially when he came up against old foes like Black Hand. Though he didn't want to go back on his word to the Green Lantern Corps, he still sought the power and respect that the title gave him. To this end, he set out to gain the very similar power ring of the supposedly deceased Sinestro.
He eventually found the ring on the Green Lantern's home base, the planet Oa, using it to start a new life for himself as a superhero. He typically just went by his own name, although the title Yellow Lantern was thrown around as well. He sported a street clothes version of his old Green Lantern jacket costume, giving him a bad boy image fitting his character and the era. He and Green Lantern Kilowog would learn that instead of charging like a Green Lantern's ring, the Qwardian yellow ring gained power by absorbing Green Lantern ring energy. He used this new power to rejoin the Justice League, though he and his teammates were defeated in battle against Doomsday. After an altercation involving a clone committing crimes while masquerading as him, Gardner took the superhero identity of Warrior.
Guy Gardner: Warrior
The return to action and a new codename didn't stop Guy's problems, however. Hal Jordan's becoming Parallax wreaked havoc on both the Green Lantern Corps and Gardner's yellow power ring. To compensate for his, he wore a bulky armor designed by Booster Gold. He never particularly liked this suit, despite the vast strength that it provided him. It was eventually replaced with a power suit created by his ring.
Guy passed up the Guardian's offer to become the last Green Lantern, with Kyle Rayner being their next choice. Eventually, he and a group of other heroes went to investigate what happened to the Corps. They were ambushed and defeated by Hal Jordan, who had fully succumbed to the Parallax identity. Guy was able to trick him into thinking that he was already dead with a construct of himself on a pike, using the element of surprise to briefly get the upper hand.
Things would take a turn for the worst, however, as an enraged Parallax not only destroyed Guy's armor and ring, but also sent him back to Earth missing an eye and in a coma from the extreme injuries he had sustained. Eventually, he would learn of his Vuldarian DNA, using it to become a shapeshifting hero and heal himself of his injuries. When Hal Jordan and the Green Lantern Corps would be restored years later, Guy's alien DNA would be overwritten, with this point in his life being treated essentially as a bad memory. He would once again wield an emerald ring, and since then, yellow rings have once again become synonymous with Sinestro and his forces.