After My Sister Disappeared, My Brother Became Invincible

[No CP+easy+no system+unpleasant writing+no rebirth+no time travel+no live broadcast] [Please scroll to Chapter 75 to skip the brother-sister plot] [Introduction 1] Thousands of years ago, there was a big change. Unknown world fragments roared in, violent collisions, the world was severely damaged, part of the space collapsed, biological mutations, mutated beasts were rampant, civilization regressed again, after two thousand years of recuperation, mankind once again ushered in stability, the world once again made a joke, a time disorder, a new machine race joined again, and mankind was once again in trouble. After that, the three races coexisted, but... [Introduction 2] Song Mubai has only one weakness: his sister. Song Mubai only has two wishes: to protect his sister and for world peace.