Hikari Sakishima  

Hii-kun, 先島 光

One of four childhood friends from Shioshishio, this individual possesses a short temper and frequently scolds Manaka for her errors, despite harboring deep affection towards her. He is the son of the Chief Priest who serves the Sea God in Shioshishio. Initially, he holds animosity towards individuals from the surface, but after gaining insight into the connections between humans on land and those living beneath the waves through Akari and Itaru, his perspective gradually shifts to recognize that there is no distinction between people from the two worlds.