IIRC, he posted this for free on his Pixiv account like a year after the initial release. I guess he profited really well from this release that he gave it out to the public.
Heh, wow, I've got not a clue about any backstory or setup on this one, but it's one great little one-on-one rape scene, he tore into her ass for damn near each and every page, damned nice stuff, thanks a lot for sharing :)