God-Level Power, I Killed Randomly in the 749Th Round

(749 Rounds + slaying demons + genius + decisive killing + no procrastination) Cao Liu traveled to a world where demons were rampant and was bound to a golden finger when he was born. However, he waited 20 years and was unable to activate it. One day, the guard Lao Wang mutated. After the successful kill, he finally activated the [Killing System] Killing monsters will make you stronger. And obtained the SSS-level ability - Blood Demon Lord Dropped out of school directly, joined the 749 Bureau, and embarked on the invincible road of slaying demons. "What?! Kill the calamity-level demon directly in the spirit-gathering realm?!" "Massacre more than 80 cult members on the highway?!" "Zeng Jin's number one young man is in his hands, and he can't hold on for even one round?!" "When did Bureau 749 have such a ruthless person?!" "What's his name?" "Cao Liu! I heard that he kills people without batting an eyelid! He cuts him down if he disagrees with him! He is nicknamed - Blood Knife Shura."