I reincarnated in my favorite novel as Darkness

an ordinary 18-year-old boy who loved to read novels about reincarnation, died after reacting to a robbery, but did not expect to be reincarnated in his favorite novel. What he didn't imagine is that he wasn't the main character, nor the villain, much less an extra, he was someone that all existences feared, demons, angels and gods, he was the unknown, the fear, the despair of his enemies. He was someone who should have been dead by now...he was the darkness. (Summary for those who don't understand, he is a being that can face the creator of all beings, someone who was born together with the creator.) (A war was fought in the past between the creator and the darkness, although the creator won the war he never managed to kill the darkness and charles was reborn as the new darkness and will wreak irreparable havoc on history.) (I don't speak English, so it is possible that there are grammatical errors): sorry)