I Really Have a Salvation Ark

I never expected that the great captain of the Ark of Salvation would actually make an emergency landing on Earth. But what's even more outrageous is that the people on earth don't believe that he has a salvation ark... But one day, he will become a great ancestor sung in human epics in the new era. PS: This is a story that takes place at the end of the era. The protagonist helps mankind resist foreign enemies and build refuge bases, giant walls, and floating cities...