Yoru no Umi de Otsukisama wo Tsuru

In the stormy ocean, you encounter a mermaid. Then you take a job at an inn with some girls, living with them in a strange village. Who will you choose as your bride? While reeling in the moon, a dog fisherman speaks, a certain legend of the sea.

Yoru no Umi de Otsukisama wo Tsuru is a freeware story-heavy adventure/RPG made in RPG Maker 2000.

Starting with Yoru no Umi the games are even more heavily story based with virtually no combat. It has the highest amount of endings based on choices you made throughout the story and which girl you pick for your love interest. Just like in TK3 you can choose between a male or female protagonist - the game more or less becomes a yuri harem if you play as a girl.