Make a Contract with the Void Shadow Beast at the Beginning and Kill the Whole World

[Rebirth + Beast Control + Decisive Killing + Revenge + Not the Holy Mother] In his previous life, he was a genius trainer, but he was betrayed by his girlfriend and brother, and died in hatred! In this life, Gu Yue Shen Yan returned with overwhelming resentment, returning to an era when the secret realm descended and beast control was respected! Be the first to contract a BUG-level ancient species at the beginning - the Void Shadow Beast! Sneak in the void, eat shadows to live, and kill with one blow! In this life, kindness must be repaid and hatred must be avenged! Kill the corrupt head teacher and bloodbath the enemy's wealthy family! Refining the beast, escape thousands of miles, and transform into a night Shura! The former Notre Dame school belle was admitted to the police academy and vowed to bring him to justice. "Shen Yan, why did you fall into darkness?" "Because this world has never given me light!" Let's see how he uses the memory of his past life and the power of shadow to stir up the storm, crush wealthy families, and make all enemies tremble and kneel in fear!