u/Few-Crow5737

I am looking for a 2010s medieval anime with a hand-drawn style where a character transforms into a six-legged fox beast after taking a curse. The ending shows a woman kissing the fox on its forehead before the character runs up a small rock to look back and vanish while the party watches. I am not sure if this was a movie or a TV series, but I remember seeing it on television.

I am also not sure if the plot involved a huge beast attacking a castle and biting the character, or if the curse was specifically a demon king curse, as parts of that memory might be mixed with another show.