The Fire Hunter Hikari no Ou English Subbed

Outside the magical barriers lies a world overrun by fiery beasts known as Flame Demons, and the only ones who can protect humanity are the Fire Hunters. In the dark woods where the beasts roam is where Touko, a young villager, is rescued from attack by one of these skilled trackers, Koushi. But their meeting was no accident, and a new destiny begins.

(Source: Crunchyroll)