Let the World Step into the Shadows

Partially cool text + urban superpower + Cthulhu mythology + prehistoric mythology Single heroine or no heroine Shadow King Shadow Abyss, who has been in charge of the shadows for millions of years, was assassinated by the King of Glory and the Outer God Cthulhu at the critical moment of impacting the eternal realm. Reborn in another world, relying on the origin of shadow and the power of killing, and the mysterious ancient ax to continuously become stronger; comprehending the power of death and understanding the six paths of reincarnation; the avenue of cohesion, splitting Azathoth with the axe. If the introduction is insufficient, please move to the text.