Okay, so I have a side character who starts out as the comic relief in my story but after a twist halfway through the story, it turns out that he's done some despicable things in the past that turn him into one of the main villains of the story. I am telling my story with both past and present tense. I want to know if it would be something that infuriated the reader or not. I sort of want to add the element of surprise but I don't want to break any official writing rules. What should I do??