Lolz, I was wondering this came from a few days ago....and I randomly found out today. It's funny because I thought to myself "Hey! those breasts look more familiar than they did the other day(O_o)....Oh Yeah! I just saw them on that Getchu place!"
Anyway, this CG is from a game called "γ«γΌγ³γγͺγ" or "Rune Lord." Also here are their names....
By the way, this is an spoiler, so don't look at it unless you're prepared.
The people Seigi, the protagonist, meets in his daily life turn out to be the characters of Zwei Worter, who are masquerading as normal people as part of a mission which involves Seigi. Makes sense when you consider both are made by CLOCKUP team DYO.