Lunarians are a race of people from the Red Line capable of creating fire from their body. The race is commonly thought to be extinct, with King as the only known survivor. Lunarians are mostly human-looking people noted for the following distinctive traits: large, black-feathered wings on their back, white hair, and brown skin. In addition, lunarians can make a plume of fire visibly, near-constantly burn at their back, although it can be put out willingly. Lunarians used to be known as a tribe of "gods" while they dwelled on top of the Red Line.
According to Whitebeard, there used to exist a "Kingdom of Gods" on the red continent long before Mary Geoise was ever there. However, under as-of-yet unknown circumstances, lunarians have gone nearly extinct, with but a single survivor of the tribe currently known. The World Government seemingly hunts lunarians around the world to this day, rewarding anyone with a handsome sum of 100,000,000 Beli for any tip-off about a lunarian's whereabouts. When Kaidou discovered King, then known as Alber, in Punk Hazard, he noted that the Government would never give him up. Accordingly, lunarians are one of only three races not present in the nation of Totto Land, where various races of the world unite. For this reason, Charlotte Linlin has expressed her wish to recruit King into her crew, so that she can have a lunarian reside in her nation. Lunarians possess the ability to "ignite" their body and manipulate the fire they create. Additionally, their physiology somehow grants lunarians incredible physical resilience, allowing them to thrive in any natural environment. They lose their durability by turning off the flames burning on their backs but gain extra speed in exchange. Unlike the inhabitants of Skypiea, the lunarians' wings are functional and allow for at least gliding through the air. Lunarians have the ability to emit fire from their bodies that they can control and weaponize in combat, such as using flames to boost the power behind their melee attacks, to unleash powerful fire blasts, and to shape their fire into constructs, even very large ones. At their strongest, King's flames are shown to be so potent, they appear to take on the consistency of magma. It is unknown if excessive use of these flames causes any kind of drawback to the user. In addition, lunarians are noted for their incredible physical toughness, something that supposedly contributed to them being known as "gods" before going extinct. The surviving lunarian, King has been described by Queen as a "monster that can survive in any natural environment". Furthermore, when the flames that burn on their back are turned off, lunarians seemingly lose said characteristic endurance, although this comes in exchange for a massive boost in speed and agility, allowing members of this tribe to reach speeds faster than the untrained eye can follow.