Life With Monstergirls

An ecchi (playfully erotic, no actual smut) harem romantic-comedy manga themed around monstergirls. Created by Inui Takemaru, it is a spiritual successor to his more hentai-flavored "Life with Monstergirl" oneshot doujins.

The basic plot is simple: a Japanese everyman protagonist lives in a world where various monster races have revealed themselves living right alongside humans. Now, there is an exchange program going to help both species better adjust to each other. Initially, our hero is playing host to one monstergirl; Miia, a playful, flirtatious lamia who is very interested in him - completely ignoring that sexual relationships between humans and monsters are, initially, completely forbidden and he would get into a lot of shit if he gave into her advances. Thanks to the case manager, Ms. Smith, being a lazy asshole (she blames it on the fact she's under-budgetted to do her job properly), he keeps picking up more monstergirls to live in his house, and accidentally encouraging their romantic interest.

Currently, aside from Miia the lamia, the harem-members are Suu the Slime, a Harpy, Centorea the Centaur, a Mermaid and Rachnea the Arachne.

Since this is a Japanese creation, although monster males exist, they follow the standard trope of being hideous fucks in contrast to their sexy females. Centaurs in particular have it bad, to the point that centaur stallions have begun resorting to adapting the racehorse metholody of "mare teasing" (in this case, using a pretty-looking, sweet-natured human guy to get the centaur mare horny, then the stallion pounces on her and rapes her while she's ready) to breed.