Extremely Cold Apocalypse: Start with an Underground Fortress

[Invincible, girl protagonist, sissy system, not the Holy Mother, e, try to be as realistic as possible] The entire world was hit by a rain of ice balls in just one night. Since then, the earth has fallen into a never-ending extreme cold. But I gained Coco's favor before the end of the world began, and unlike other systems, I could actually squeeze a body for the system! Start with an underground doomsday fortress that can be upgraded with just moral points. Moral points can be gained for both good and evil, good and evil can happen in an instant! Underground fortress, underground boat, land speeder! Flying giant ships, floating fortresses, and sky cities! Space giants, orbital bombings, satellite cities! I will upgrade infinitely, from the ground to the sky! Suddenly, I met a Japanese who was not polite. Not much to say, four hydrogen bombs are enough to destroy your clan! When an American who knows no fear comes to me, Then you should see the magnificent scene of the American continent being lifted up! When I want to destroy you, you should not accuse me of doing something wrong, you should reflect on what you have done! I will build six giant statues on the equator, comparable to Everest, and people all over the world will worship me! I will establish a faith, and only devout people can enter my city!