I Can Become Stronger by Killing Monsters!

Xu Ning discovered a very scary thing. Even a fourth-level monster couldn't stand in front of him for 3 seconds, but he still couldn't break through to the second level! As the clouds dissipated, Xu Ning was trapped in many traps and narrowly escaped death. When the powerful demon clan couldn't help but rescue him, a man in black stopped the powerful man. I'm dead, I don't seem to be dead, I'm in nirvana! It has also broken through to the third level!