GATE - Thus the JSDF Fought There

From the introduction: Welcome to Earth! This world might look like yours on the outside but it takes place in 20XX! Yes really. Anyway it is about to have a bit of an upheaval with the appearance of a gate to another world in the Ginza district of Tokyo, Japan. There the Imperial Army will spill out, killing, and enslaving many of the local population until the JSDF show up to stop them. The other world, AKA the Special Region, would be reminiscent of the medieval era if it weren’t for the dragons, elves, beastfolk, gods and their followers running around. It’s practically a world filled with magic and riches! Fancy that, you will start off in this world the day of the invasion. Do try to be entertaining now.