ChaO

In a world where humans and mermaids live side by side, Stephan is a mild office worker at a shipbuilding company who expects little beyond his familiar routine. Then Chao, a princess of the mermaid kingdom, suddenly appears and asks him to marry her.

Before he can make sense of the proposal, Stephan finds himself sharing a home with her. Chao's affection is wholehearted, unpredictable, and impossible to ignore, gradually breaking through the emotional walls he has built around himself. What begins as complete bewilderment slowly grows into a romance neither of them expected.