It was a fantasy harem. It has a male character who had the ability convert Monster girls into weapons. I remember a wolf girl, bird girl and a Golem loli girl.

I also remember I've of the enemies he defeated was a obsessive hunter who had a cloaking tank like vehicle with a sniper, and i think but not certain that the main character and the villans were from the modern world. Please help I was talking to my girlfriend about the manga but can't find it and it's driving me mad.

Never mind, i found it. Is called 12 Beast