My Reborn Ideal Doomsday Fortress

In my previous life, I was just an ordinary takeaway boy, working at three o'clock and one line every day. The end had come, and I didn't know what happened, but I was killed in his bloody mouth the moment I opened the door to deliver food to a customer. I must be fully prepared for this rebirth! Prepare for the doomsday in advance and build a top-notch doomsday fortress that will live up to who I am after this rebirth. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.