Rampage into Another World

Obviously I just want to celebrate my sister's birthday! Why is the place where my sister works so weird! ? Great sword, heavy hammer, ballistae, musket! Leather armor, cloth, iron armor, swimsuit! ! ! ... Cough... Cough... How did I get to the stronghold in another world! ! ! In this case, I am here, and I will try my best to contribute to the peaceful and safe development of the world...