This is admittedly an old Pokémon that I made, there’s no doubt about that, but here’s the lore that I had for it, as well as dex entries.
Flameroar is a legendary Pokemon that resides in the Draco region, and is one of the last two Pokemon Arceus had created, using a tremendous amount of energy to create the guardians of light and dark, and to protect the world from an existential calamity.
Pokémon Light: Flameroar is believed to be judge of light, creating spheres of light so bright that they could be considered miniature suns.
Pokémon Dark: this Pokémon is said to eradicate those who threaten the cosmic order with holy fire and radiant light.
by BOBEYOPDRAGON1001