Where the Mountains End and Rivers Flow

For the past few centuries, the Three Realms have seen upheaval after upheaval.

Seeking a place to call their own, the Yao launched a massive military campaign, invading both the Heavenly and Demon Realms. The Human Emperor lost the Mandate through his failings, and the feudal lords and rebels rose up to restore order... War swept across the Three Realms time and again. Then, two hundred years ago, the gods and demons joined forces and finally put down the Yao rebellion. A few years later, a wise ruler established a new dynasty in the human world.

Peace reigned across the land. As if moved by this, in the fiftieth year after the Yao rebellion was quelled, the benevolent beast Zouyu descended into the world at West Kunlun.

...None of this seemed to have anything to do with Black Dragon Mountain. At its foot, an obscure little yao ran an inn; atop the mountain, an unremarkable young master read light novels and basked in the sun... Life passed quietly for centuries, and no one ever thought to look beyond the mountain.

Until one day, a young woman in white walked into the mountain.

A few things to know:

1. A somewhat oblivious goddess x a gentle (?) Demon Lord. One-on-one romance, happy ending.

2. Not a wish-fulfillment novel; slow burn.

3. A lightly ensemble-focused story, perhaps about a group of good people helping one another survive in troubled times.

Theme: Though calamities may sweep us apart, our hearts endure.