Shin Mazinger Shougeki! Z-Hen

When poor detective Kuro Daijuuji accepted his first well-paying job, he had no idea what he was getting himself into! The request: to find a magical grimoire for Ruri Hado of the Hado Financial Group. After searching all of the bookstores and antique shops in Arkham City and finding nothing, Kuro is just about to give up when a grimoire happens to fall out of the sky and land on top of him... in the form of a young girl! Her name is Al Azif; and she is being chased by the Black Lodge, a group of evil mages. The two find themselves surrounded, and in order to survive Kuro is forced to enter a contract with Al and become the pilot of the Deus Machina Demonbane.