It’s about two amphibious characters.
Guide to Find the Phioran Couple
The female Phioran is on the west coast of the beach south of Basil.
Her husband is in the river acting as a moat between Rholand and Farnsport.
You have to jump down into the river from the north side of Farnsport (east) and go through the water all the way to the south end to find him.