Jugigo Sipeun Naui Jeonbong Wangja-nim

Jeon-Bok, the arrogant prince of the underwater kingdom, is pushed to the land where humans live in search of the 'Bride of the Sea' who can control ancient weapons in order to defeat Queen Margo, who opposes the destruction of humanity. He is rescued by Eun-Gyeol, the country's top free diver, and comes to live in her house.

(Source: Mr.Blue, translated)