People Exorcised Demons in the Middle Ages, but I Am the Big Devil

"What's your secret to being the best exorcist?" "Empty the magazine first. If one magazine is not enough, use two." "Sir, I guess Satan needs you tattooed on him." "I am Satan Benza." Wang Shiyi traveled to the Middle Ages and became an exorcist. Good news: I am the most awesome demon, Satan. Bad news: His abilities are sealed. He only remembered that his demon army stabbed him in the back, so Wang Shiyi decisively became an exorcist and started his own exorcism journey. But as Wang Shiyi slowly unlocked the seal, the lost memory was restored... "So it turns out that I am the traitor?!"