NakiNagi

A quiet witch meets a girl in love. Nakika was once a feared with of the deep sea, but has started a life on the surface to learn about "human emotions." Nagisa is a naive romantic and Nakika's best friend—and although she might not always understand Nagisa's infatuation, her compassion for Nagisa is deeper than the Pacific Ocean! As she uses her magical powers to support Nagisa's quest for love, she gradually learns about “human emotions. Follow the 1000% wholesome story of a girl in love and her watchful guardian!

(Source: K MANGA)