Faeries (1981)

Animated TV special based on a series of popular fantasy books that have their basis in Irish folklore. Young hunter Oisin is returning with his family from an unsuccessful hunt. He notices a fawn and strays away from his group. The fawn turns out to be a beautiful fairy princess who asks him for help. Her father, the fairy king has accidentally given life to his shadow. When it became strong enough it ran away to feed on darkness of the forest and prepare trolls, witches and other creatures to take over the fairy land and bring upon the eternal night over the land forever. The king is certain that young Oisin with the help of the king's assistant, shape-shifting Pan-like goat-boy Puck, can stop his evil shadow. However, they must find the location of the shadow's dark castle first.