Sekai ni Hitotsu dake no R

Urus lives in a world dominated by chaos and darkness, seeking vengeance for the death of his family at the hands of demons. He learns of a tavern called "Kelg's pub," where reincarnated heroes gather to find allies against the demon king. Hoping to join one of them, Urus goes to the pub and undergoes a summoning ritual that classifies him as the weakest and marks him with the letter "R." Through this experience, he begins to uncover the deeper darkness of his world. Questions remain about the meaning of "R," the purpose of the ritual, and the true nature of the darkness surrounding him.