That was always the problem with Kampfer. While it was yuri oriented, like with so many other yuri themed manga they didn't leave open even a chance that there would be other maybe hetero relationships. The other guys aside from Natsuru did they even have any names? Throw in some other named males and have them hit on Natsuru and the other girls. Don't just make them joke characters. I'm tired of all these futanari Kampfer doujin.

Anyway, why does this doujin have a different cover here: http://www.x-9.sakura.ne.jp/index.html

What's the difference between the two?

Base +7, Ragnakor -7, staketo -6, xaelath -6

http://www.doujinshi.org/book/346254/Onnanoko-ni-Natte-Kanjiru-Q/

Base +55