Hikari no Ou

Summary:

A great forest, infested with flameling creatures and other fallen beasts, covers the world, and pockets of humanity live in small protected communities. Due to a special weapon used in the Last War, human beings spontaneously burst into flame even when merely getting close to a small source of fire. The only safe energy source for humanity lies within the bodies of flamelings, and the duty to hunt them falls to the sickle-wielding firecatchers who brave the depths of the great forest. Among the firecatchers, they whisper tales of one who would be "Firecatcher Lord," an individual who will be able to harvest the fire of the thousand-year comet, the "Wandering Spark" that has flown in the sky since it was sent up before the Last War, but is now returning to earth.