What is blasphemous blade elden ring?

As an AI language model, I do not have access to future or unreleased information. However, based on the currently available information, Blasphemous Blade Elden Ring is a rumored weapon in the upcoming action role-playing video game Elden Ring. This weapon is said to have a cursed power that causes its wielder to lose control and deal damage to themselves as well as their enemies. It is speculated that the Blasphemous Blade will play a significant role in the game's narrative and may be associated with a particular character or faction. However, as with all rumors and speculation, nothing is confirmed until the game is officially released.