Fan Banjin was an intern ghost officer at the Chinese Underworld's Palace of the King of Hell. In reality, he was a highly accomplished student whom his cousin Fan Wujiao, the Black Impermanence, had parachuted in to learn the ropes of underworld administration...
He'd only wanted to be a laid-back young man, work as a runesmith, and live an ordinary life.
When the Black Impermanence realized that his younger cousin was far too content with an easy life, he decided to send his beloved cousin to the Japanese Underworld as a liaison so he could learn the ropes and gain some experience. Little did he know that once he left, he would never come back.
When the Black Impermanence saw his soft and adorable cousin being carried off by that dark-faced man from the other side, who wielded a spiked club, he wept and bit through a little handkerchief.
[This story has plenty of original worldbuilding. It mainly explores the differences between the Chinese and Japanese underworlds and the everyday lives of their inhabitants. The main plot is probably the love story between Hozuki and Banjing.]
That's right. This is a story about a gentle, adorably clueless powerhouse being taken home right before your eyes.
There are no crossover elements, the worldbuilding is normal, there's no angst, and the story follows a sensible logic. Since I'm writing this for love, I don't plan to sign a contract or put it behind a paywall. Let's keep things simple.
Theme: If you can't find the kind of story you want to read, write it yourself