Gu Family Book

Choi Kang Chi is a half-human and half-mythical-creature who was adopted by the lord of the Hundred Years Inn. He was the son of Gu Wol Ryung, the guardian spirit of Jiri Mountain, and the human Yoon Seo Hwa.
Dam Yeo Wool is a martial arts master and daughter of the leader of a secret organization protecting the region. She was sent to the Hundred Years Inn to observe and protect its lord.
They met at the Hundred Years Inn, the most popular inn in the region, and fell in love with each other despite Choi Kang Chi being a half-human. When their world turned into chaos, it is up to Choi Kang Chi to put it back into order; and up to Dam Yeo Wool to ensure that Choi Kang Chi's half-mythical-creature side does not get the best of him.
(Source: Snoworld at MDL)