How To Create & Write An Arch-Nemesis

What an arch-nemesis is

An arch-nemesis is essentially that one antagonist the main character just can't stop locking horns with. While other antagonists might be defeated once and never heard from again, the arch-nemesis comes back again and again. As they repeatedly clash with each other, they usually can't help but get to know each other relatively well, and their frustrations with each other escalate and grow into something very deep and personal. Thus there is always a personal stake in their fights, and they tend to know each other's weaknesses better than anyone else.

Sometimes an arch-nemesis began as a friend, colleague, or family member of the protagonist, but due to irreconcilable differences of opinion over something important, the pair ultimately fell out with each other. Sometimes one or both of them have never truly forgiven the other for the "betrayal." Sometimes one or both of them desires reconciliation, though whether it's actually possible is another matter. In any case, their mutually-exclusive viewpoints frequently lead them into conflict with each other, where deeply conflicted feelings will often abound.

And of course, sometimes it's a bit of both.

And that's pretty much it! While other traits and characteristics help flesh out the arch-nemesis, this is the heart and soul of what makes the arch-nemesis.

Traits and attributes the arch-nemesis needs

You may have heard that an arch-nemesis "needs" to be the opposite of the protagonist in some way (EG, if the protagonist is the 'brawns,' then the arch-nemesis is the 'brains'), or that they must be the same as the protagonist in some way (EG, they must both be idealists). But this isn't always the case. While building an arch-nemesis this way does often work, it isn't always necessary. So let's take a look at what every arch-nemesis actually does need:

Something to end up in conflict with the protagonist over. The crux of the whole protagonist/nemesis dynamic is that they just keep fighting each other. Obviously, "she's a hero, he's a villain, that's just what they do!" isn't going to cut it. An easy way to set this kind of scenario up is to give them two mutually-exclusive goals that they are equally willing to fight for. For example, if you have a hero who thinks everyone should be free and equal while your villain is merrily enslaving people, then your hero will naturally go and try to put a stop to that noise and thus conflict will ensue. Or maybe they both want everyone to be free and equal, but the villain has a rather horrifying way to go about it (like turning everyone into brainless fungi) and your hero finds this to be an unacceptable solution.

The means to avoid getting caught (at least for good). Whether it's money and lawyers, good political connections, the support of the government or just the wits to plan out an escape in case things turn sour, an arch-nemesis needs to have a way to avoid getting taken down. Exactly what it ought to be depends on the type of story and character you're trying to write. (A wealthy and well-connected politician can afford to be dimwitted on a regular basis; a lone criminal or rogue operative type can't.)

Coherent motives and rationales. Since an arch-nemesis is going to be around for the long haul, any holes in the character's motives and rationales are all the more likely to be noticed. Don't give into the temptation of trying to claim the character is "just insane," either - not only is it just lazy writing, it's also not even how mental illness works. Instead, try to work out what the antagonist is trying to accomplish, why the antagonist wants to accomplish that, why the antagonist thinks these particular methods and means are acceptable, and why the antagonist is doing things this way as opposed to any other way. If you find yourself struggling to think of answers, On Designing & Writing Oppressive Governments In Your Fiction, Factors That Contribute To Abusive & Dysfunctional Systems/Institutions, What Writers Need To Know About Predatory People, and Mindsets & Rationales That Lend Well To Villainy might be useful.

A few tropes and things to avoid

Some tropes and such can undermine the credibility of the story or its characters in some way, and so are probably best avoided. Here are some to watch out for:

Having the antagonist pick a fight with a protagonist who hasn't actually done anything yet. Since the antagonist presumably has an actual goal here, why go out of the way to attract the attention of someone who might get in the way and muck things up? If anything, the antagonist should be trying to avoid attracting attention as much as possible. Even if the antagonist is worried that the protagonist might find out and try to interfere at some point, it's better to just prepare to deal with that if it actually happens and to keep out of sight in the meantime.

Assuming that obsession must be rooted in some kind of attraction. Making the characters attracted to each other isn't always a bad thing, but some people assume that obsession must imply attraction and so end up shoehorning it into places it really doesn't belong. Fortunately, it's a simple matter to write obsession without attraction being a factor in it at all. The antagonist's obsession might be likened to wanting to destroy a mosquito that has left behind a dozen itchy bites in its wake, while the protagonist's obsession might be likened to a scientist determined to find a cure for a terrible illness after seeing numerous people die from it. (If neither one of them is exactly a hero or a villain, you might switch these around, use one of them for both characters, or go with something else entirely.)

Taking the obsession from 0 to 10 practically overnight. You've probably heard of something like this one before: a superhero stops the sinister plans of a supervillain for the very first time, and suddenly this supervillain is swearing vengeance on the superhero and everyone the superhero loves for all eternity. Let's face it, this scenario is about as realistic as swearing to love someone for eternity after the first date. Like any other relationship, the hate-based relationship between the protagonist and the arch-nemesis needs built up over time, or else it feels hollow and contrived.

A more reasonable reaction to being attacked by a superhero for the first time would be to go, "Okay, that guy is a thing I gotta worry about - now what can I do to make sure he or somebody like him doesn't get in the way again?" Once the superhero has gotten in the way about three times, then it starts making sense for villain to get a little more proactive in doing something about the hero. Only when those efforts have failed a few times would it really make sense to try more indirect methods like going after the boyfriend or whatever.

(While there are some people who might actually swear vengeance after a brief conflict with someone, remember that an arch-nemesis needs to be someone who can actually stay focused on a long-term goal. The kind of person who gets that worked up over one setback is not usually the type of person who is good at that. Besides, how is a villain who makes a point of enacting bloody vengeance on anyone who ends up being a minor inconvenience going to have time to get anything else done?)

Making other characters idolize the conflict in some way. As readers or viewers outside of the story, it makes perfect sense for use to look at it and see deeper meanings and themes (whether intended by the writer or not). We also understand that without these two characters having the strong enmity they do, there would be no story at all, and thus in a sense these characters really do "need" each other. It does not make sense for characters in the story to start thinking like this unless they are highly eccentric or delusional. Most people don't look at real conflicts and see an epic legend playing out. They see a bad situation they really just wish would stop so things can calm down and life can move on.

Likewise, if at any point an antagonist says to the protagonist, "Ah, but where would you be without me? Your life would have no meaning!", this should be taken as a sign that the protagonist really has an unhealthy lifestyle and should really probably do something about it, not as justification to let the conflict continue indefinitely. If the only thing that gives your protagonist's life meaning gets innocent people hurt or killed as a consequence, that is really messed up. Why is your main character's unhealthy hobby more important than other people's health and lives, exactly?

Confusing petty drama for epic drama. Epic drama includes things like the fate of a people or a world hanging in the balance. Petty drama includes jealous rivalries, bitter breakups, and fretting over which sibling Mother loves best. You can write a good story about either one, but you don't want to try to write an epic story where nothing epic actually happens, or where petty drama is treated as more important than the actual epic drama. This isn't to say that petty drama has no place in an epic story, though. Good uses for petty drama in epic stories include giving giving characters something to work past so they can actually tackle the big issues, something for characters who are intended to have skewed priorities to obsess over, or for comic relief.

Optional ways to spice things up

The following is a list of optional ways you can make things more dramatic or interesting, depending on the needs and goals of your own story:

Make the audience see themselves in the protagonist... and then make both the protagonist and the audience see themselves in the antagonist. This is a great way to build up some personal horror. First you give your protagonist personality traits that your target audience will likely relate to, good and bad. Then you create an antagonist whose evil actions are the result of failing to check and balance these traits - for example, anger issues that haven't been dealt with in a healthy manner, or a desire to create a peaceful utopia without caring what the very people who will presumably be living in it actually want. When the protagonist realizes what's up with the antagonist and thinks with horror, this could be me if I'm not careful, many readers/viewers will have that realization, too.

A caveat, however: if this whole thing culminates in the villain asking "what makes you different from me?" and the question could be accurately answered with something like "The difference is that I try to be a decent person and do the right thing these days, whereas you're still reveling in being awful and refusing to grow as a person," or "The difference is I'm the one trying to stop a mass murder from happening, whereas you're the one trying to commit the mass murder," then there's nothing especially deep or horrifying going on, and a savvy hero should not be caught off-guard by this. (Though it could be fun to see the protagonist get one over on the antagonist with an answer like this!)

Give the protagonist and antagonist something to talk about. Conversations can be used to have them learn more about each other, to show us how they feel about each other's choices and worldviews, and to try and tempt each other into straying from their paths. This is one reason it can be useful to give them something in common, as common ground can make it easier for them to start and hold a conversation. Still, if they're extremely alien to each other, simple curiosity could motivate them to try and learn more about each other. Basically, as long as they have something to talk about and a reason to talk about it, it's all good.

Make it a complicated situation where neither party is entirely innocent or guilty. This can be very tricky to write well, but if it's done right it can make for a great story! See How To Write Sympathetic Antagonists Without Endorsing Or Excusing Their Actions, & Without Making Your Protagonists Seem Heartless for tips. Also don't forget that if your antagonist is sympathetic, you will have people rooting for redemption, so you might want to take a look at How To Redeem A Villain. (Seeing an arch-nemesis turn into a snarky rival/frenemy/ally can be a lot of fun; and seeing two longtime enemies sort out their differences, come to an understanding, and move on with their lives can be a great way to wrap up a story!)

In essence...

Essentially, an arch-nemesis is someone your protagonist repeatedly comes into conflict with in such a way that they have personal feelings tied up into it, whether it's because they've irritated each other so much, or because they used to be close, or a bit of both. The best way to make that is to give them two mutually-exclusive goals they're both willing to fight for and give the antagonist the means to avoid getting taken down for long. Beyond that, what you should and shouldn't do comes down to what best serves your story's purpose and keeps it sufficiently plausible and entertaining.