Ningyo no Iru Ori

Reunited after eight long years, my ex-lover, who is now a merman somehow, was sitting right there in the bathtub in my own room. His eyes, unchanged after all this time, gleamed with murderous intent. This is a story about how to deal with a merman—who happens to look just like my ex-boyfriend from high school—after he suddenly decides to take over my bathroom. He seems hell-bent on taking my life for some inexplicable reason, so now I'll have to try and survive by any means necessary. [Translated from Novelgame]