Shuten Douji is a powerful demonic being from the Fate/Grand Order universe, who is often summoned to make use of her formidable martial powers against fearsome enemies. She is also a cute loli. The gentlemen in this doujin have little interest in her ability to fight legendary battles, and all the more interest in gang-raping her tight loli ass. This is their story.
I remember this and going WHAAAAAA
The script is actually really fun, the guy teaches you how to get high on brain chemicals. Someone else’s, of course.