He died excruciatingly. He died living in hatred. Hating the people who hurt him. Hating the people who abandoned him. Hating humans. He died without releasing his darkest desire. So he pleads for another life. Where he can unleashed his desire. The desire to kill. Kill those who puts his life in despair. And the Sovereign of death who's waiting for a successor heeds to his plea. Thus he was reincarnated. But in a parallel world where... Humanity have magical abilities. Where humanity is peacefully living in an enormous tower. Hence, he was... Born as the tower's invader who level up his monster summoning when he finished a certain mission. A mission to kill. Kill the people he hated on his past life that he will meet in every floor of the tower. And just like that... He was born to kill. And his ultimate mission: Kill the Tower's emperor. The person he loathed the most.