Monster Musume manga volume 15 features story and art by OKAYADO.

Miia is suddenly called back to the Lamia homeland when a disagreement amongst the various Serpentine folk (the Lamia, Echidna, Melusine, and Medusae tribes) threatens the Interspecies Cultural Exchange, which would mean Miia would have to return home for good. It’s up to Kimihito to prevent this. But to do so, Kimihito will have to satisfy all four Serpentine tribes in a depraved tournament of flesh. Will Kimihito succeed, but lose Miia in the process?