So I’ve been wrestling with a problem while working out how to tackle my story's "Final Boss". A large part of the book revolves around a hero with a special power using it to hunt down and stop a serial killer who also has a special power, because due to third party threats the powers have to remain a secret and thus he's the only one who can even begin to figure out how this guy's committing his crimes. Ultimately he fails to figure out who he is due to a last-minute bit of deception on the killer's part, but managed to escape from, and eventually defeat him in battle one on one. One problem I've always had with this idea is that it basically means that we know next to nothing about the person who winds up being the subject of the dramatic climax of the final battle aside from his stated motivations regarding why he's hunting down the people with powers. In essence everything we learn about him, since his identity is supposed to be a secret, is stuff that has to be learned during the final battle, which feels cheap, or at least way less satisfying than it could be. But a potential solution recently came to me: What if it turns out that, without either of them knowing it (or possibly ever even figuring it out), the villain is actually the hero's biggest online friend (which is a big deal because until the start of the story he doesn't have any friends IRL)? If I did this, then I could either use two-perspective dramatic irony or a reread-bonus plot twist to provide additional background on the antagonist's motivations and circumstances. The problem is, I can't decide which I should do: Should it be dramatic irony, where somewhere around a third of the way into the book I reveal that the killer's the guy the hero's been talking to periodically, and then show both (or at least one and a half) sides of this mystery like something out of Death Note? Or should I have it be a plot twist after the villain dies, or at least something heavily implied by the ending, to completely re-contextualize and provide new meaning to the hero's periodic chats with him upon the second read-through? Does anyone have any advice about the advantages and disadvantages to each approach?
I've always been more of a fan of dramatic irony. I dunno, twists are good, but the feeling of dread you would evoke from having the reader know that these two are best friends as well as mortal enemies, without one of both of them not knowing it, would completely out-compete any shock value from the twist. It's even better if you let the villain know this, and use it as a way for him to be one step ahead of the hero, as well as throw him off of his investigation into the killing method. Your audience will be going through the book after the reveal like "Oh no, he's gonna trick the hero again!", "No hero, that's obviously wrong, stop letting emotions rule out logic!", and, once the hero figures it out/the villain is defeated, you'd evoke a massive wave of euphoria now that the tension is finally gone. But that's just my two cents. I've always felt that dread beats shock any day. Hell, it'd be even better if you can clue the reader into this fact without explicitly showing it, because then the reader will have the satisfaction of figuring it out on their own. The problem with this approach is that you risk the reader never figuring it out until it's revealed during the final confrontation.
I don't really know what a dramatic irony is lol (have heard of the term though). However, I always love things that have a changed meaning with added depth the second time round. So personally, I'd go for the second option of recontextualising the whole chat/friendship on second reading. Love the idea that the villain is the hero's best online friend, by the way. It gives the reader a chance to guess at who the villain is and I love these grey relationships, grey characters where no one's really black and white. However, if he's the only friend the hero has, or the only online friend, your reader would probably figure it out way before they should that this guy's the villain. While the idea of keeping it a secret from the reader and allowing for a changed interpretation of the text on second reading is great, I fail to see how it can be executed. You'd need to give your hero more than one online friend, but then that makes a lot of floating heads. So it might be more doable if the reader already knows and you work with the reader's dread angle. But that might make a rather frustrating read if it's from the very beginning.
It's when the reader knows something that the characters do not. Like the MC's wife is boning his brother or the guy sitting next to the cop at the bar is the killer he's been after.
