Everyone knows about Silver Surfer, the most famed herald of Galactus, but many others have served as the herald to the World-Eater, including the cosmic hero known as Firelord. Before taking on his role as the herald of Galactus, Pyreus Kril was a naval officer for the Xandarians, the original home of the Nova Corps peacekeeping force.
After debuting in Gerry Conway and John Buscema's Thor #225 in 1974, Firelord's origin was most succinctly recounted in 1996's Uncanny Origins #4, by James Felder, Dave Hoover, Bill Anderson, Jack Morelli, and Jon Bobcock. This story showed Pyreus as a young cadet who got a chance to serve under his hero, Commander Gabriel Lan. This unit was a band of misfits led by the legendary Xandarian war hero on a ship known as the Way-Opener.
When Galactus arrived, Commander Lan disappeared, and Pyreus took charge. Eventually, Pyreus committed treason against Xandar by refusing a direct order and pursuing Galactus to try to find Commander Lan. However, when Galactus attacked, Pyreus sent his team to safety and took on the World-Eater himself.
Galactus offered to tell Pyreus what happened to Commander Gabriel Lan in exchange for becoming his new herald. Pyreus agreed, and Galactus turned the Xandarian warrior into Firelord. The Devourer then informed Pyreus that he saved Commander Lan from his long journey, where he had grown tired and weary, and gave him the power cosmic. Commander Lan became the Galactus herald known as Air-Walker. He faithfully served until he died, protecting his master from Ovoid warships. Galactus placed Lan's consciousness into a robot replica, but without the warrior's personality and passion. It fell in battle with the Silver Surfer and Fantastic Four. After telling this story, Galactus then wiped away all of Pyreal's memories and sent Firelord out to work as his new herald, finding new worlds to consume.
In his initial adventure, Firelord teamed up with Hercules, Thor and Galactus and earned his release from the role of herald to Galactus when they defeated the insane Ego the Living Planet. Thor offered up the Asgardian construct The Destroyer to Galactus as a replacement, and Firelord found his freedom. He also got a bonus for being utterly loyal to Galactus: he received full freedom and was allowed to travel anywhere in the universe he chose upon his release.
Firelord had many adventures in the years after his release from Galactus. After Thor defeated the Air-Walker automaton when it returned, Firelord finally gave Commander Gabriel Lan a proper burial. He then set off for his home planet of Xandar only to find it destroyed and set out for vengeance.
Firelord's most significant return came in the pages of Annihilation: Silver Surfer (2006) when he was one of three heralds of Galactus to join Nova's United Front against the Annihilation Wave. Once this ended, Firelord sought vengeance against the Centurions, the strike force that destroyed his homeworld when the Annihilation Wave began. Most recently, Firelord was back in the pages of Guardians of the Galaxy by Donny Cates and Geoff Shaw, when he was called on to help Eros try to stop Thanos from regenerating.
Finally, he returned to battle The Avengers in Avengers #29-30 by Jason Aaron, Ed McGuinness and Paco Medina, as he teamed with the Shi'ar to stop the Starbrand, a being that might end up as the most destructive force in the universe. While The Avengers fought to save the being, Firelord, Silver Surfer, and Terrax the Tamer knew the dangers and believed it had to be destroyed, putting them on the wrong side of Earth's Mightiest Heroes. However, he was also part of the force united to battle Star-Lord's father, the Patriarch, proving that after serving Galactus, Firelord was a hero protecting the entire universe.