Character Disadvantage Fragile Tokyo. The Matchstick City. It attracted rampaging alien armadas. It brought demon swarms from the deepest hells. It has been devastated by giant robots only as few times as it has been devastated by Godzilla.
Old habits die hard.
Despite the fact that the city is now covered in yards of thick mechanical armor, those who actually manage to make it INTO the city are still able to devastate the whole place with little to no effort. Extremely paranoid, though with good reason. The greatest shipbuilding, mech building, vehicle building and android building minds in the world are concentrated in this one city and have sotred their theories and designs on computers. Tokyo merely accessed these files to create the insanely powerful city you see before you. This attack causes damage in a large, circular area.