City: Global Evolution, I'm a Swordsman and I'm Back Invincible

[Invincible + decisive killing + cultivation + no heroine + source energy] Twenty years ago, the celestial spheres converged to produce source energy, which infected the entire earth, and all animals and plants began to evolve. Animals that have mastered source energy have turned into extremely large source beasts, and they also possess various strange powers. Human beings were attacked by source beasts without defense, and suffered extremely heavy losses. The birth of source warriors and source energy weapons gave mankind hope. However, the source beasts were too powerful and their manpower was exhausted. In the end, humans only had a population of more than a billion, and a joint defense zone was established. Twenty years later, the Zhou Yuyang sect in the Golden Core stage was destroyed and was sent into the ancient teleportation array by his master. He unexpectedly returned to Earth. Source Energy Technology, the Joint Defense Zone, the Ancient Martial Family, the Ancient God Sect, the military... The earth is no longer what he is familiar with. Zhou Yuyang, one man and one sword, climbed to the highest level of sword cultivation step by step in this new earth infected by source energy, and finally discovered that all the changes in the earth were caused by him. "In this case, I will destroy all the cause and effect with one sword, here comes the sword!!!"