Speaking of Monster Musume, i discovered for myself that Monster Musume has a "parallel" universe i guess.
The folks made it also made a manga called 12 Beast. This still has monster "people" in it and art very similar to Monster Musume. Its theme is more action/comedy/fantasy/scifi version of Monster Musume with lead character drawn similar to "Darling".
I've only read first volume, but it's not too bad.
Plot: Apparently, a young woman who turn out to be a Harpy, manages to goto the Earth to retrieve main character who a ninja dojo trained video gamer. (This version of Harpy's race by the way makes a semi-cameo in Monster Musume during Darling's date with Ms Smith). He taken to "Live Earth" to help save her people from attacks by mecha like creatures called Giga. A empire trying to subjugate the planet with high-tech, while rest world is mostly fantasy level tech and touch of Earth tech.
Monster girls in the manga are little but not too different from Monster Musume. Having read the former, it made reading 12 Beast more interesting to me. To me, it seems like their using Monster Musume's array of races and world setup gave it non-Romentic-Comedy flare to it and not quite as ecchi. It's nothing write home about, its nice read so far. Lastly, I won't call it a Harem thing either, though looks like it at first. None one is in love with anyone.