@Caramel Frappe:
Hmm... Simple google search actually, but I've done some snooping for you. Looks like it was originally posted on a Russian anime fan site (akin to deviant art) by a Mr. Andatrik... Here comes the malware.
http://animechan.ru/41994-rpg.html
Looking in the comments it makes references to 'Monster Girl Quest'. Which eventually lead to...
Definitely NSFW:
http://monstergirlquest.wikia.com/wiki/Lamia
Absolutely no connection, from what I've seen, to Okayado, the original creator. This leads me to believe this is someone (Andatrik) having a joke at both Monster Musume and 'Monster Girl Quest' or RPGs of similar vein. Probably Andatrik loves the source material and did it up as a bit of satire...
Edit: Particularly when another comment suggests: 'This is not canon!'
Sorry.
That said, there are some rumors on the wiki page of a Monster Musume PC game being in production, so who knows?...