Global Cataclysm: I Turned in the Portal

[Apocalyptic Science Fiction] [Portal] [Alternate World] [Mecha] A natural disaster strikes, and the earth's surface is enveloped in extreme cold and radiation. An underground base established by human beings in order to survive. In order to save his sister, Mu Chengzhou handed over the portal. Since then, he has dominated the world in another world with the help of his country. For his safety, the country developed a battle armor based on Iron Man - Qianyuan No. 1! For the sake of his body, the country re-edited Taoist classics, allowing him to embark on the road to immortality! For his sister, he collected all the elixirs in the other world. For the survival of the country, he made the entire other world become the country's foundry.