Chemistry is a vital part of relationships. It’s what makes readers swoon over your couples, root for your protagonist’s entire team, and relentlessly ship your characters.Chemistry drives rivalries and romances alike, and when it’s done right it can make for compelling relationships.. Below are a couple tips for kicking up the chemistry and making sparks fly.

1. To create chemistry between two characters, construct those characters around each other.

In other words, the characters are quite literally made for each other.

Kind of like puzzle pieces, if puzzle pieces  picked fights, constantly disagreed, and had deep, unresolved feelings for each other.

One trick for this is foiling. This is when you create two characters (or two groups of characters) to be opposite one another. If the hero is hotheaded, their rival (or friend, mentor, etc.) is even tempered. If the hero is blunt, their rival has a sharp wit. And so forth. You can do this with one or two characteristics, or with a whole bunch. Foils work by setting off opposing characteristics, and using the contrast to add definition to the characters. It also makes interactions between the characters interesting because they are in a state of natural opposition to one another, whether friends or enemies.

Another thing that happens when you create foils is the characters complete one another and balance each other out. Personality-wise, each one has something that the other one lacks, and so they fit together.

Directly opposite foiling is mirroring. This is when you make two characters who may be fundamentally different, but share certain key characteristics. It can extend to having the characters follow similar (if divergent) plot arcs. Mirroring works by using similarity both to create a connection between the characters and to heighten the differences that they do have. A common example of this are cases when, on close inspection the hero and villain have quite a bit of personal overlap. It also works well in large casts, and can create a sense of cohesion between characters who don’t get many chances to interact directly.

She’s a lot like me. The only real difference is that I’m better.

When your characters mirror one another, you place them into competition. Since these characters tend to be built around a core set of similarities, you put them in a position to build off one another and to try to outdo each other. You also invite readers to compare the characters.

Both foiling and mirroring can be subtle. Without outright stating how similar the characters are or making a bold claim that they’re as different as night and day, you can show these things in the ways that they act  and allow readers to draw their own conclusions.

Also note that these techniques are not mutually exclusive. Characters may compete in some ways but compliment each other in others. The effect of this will be much more subtle than using either on its own, but it will also allow you to tailor your characters to one another more exactly, and to craft a more complex relationship between them.

2. The characters should be mutually invested in their relationship.

Chemistry arises through mutual interest. Regardless of whether the characters are friends, foes, or lovers, both of them must have a stake in the relationship. As I have said in several other articles, readers take emotional cues from the characters. If one of the characters is invested, readers will also view the relationship as something unworthy of investing in. Meanwhile, if the characters are drawn to one another, readers are more likely to view the relationship as important.

One part hatred, one part emotional investment, and a generous dash of homoerotic subtext.

Mutual investment is just as important in rivalries as it is in friendship and romance. This is one of the principal reasons for the abundance of romantic subtext between heroes and villains. When the hero and villain are well matched, and if the villain has an active presence in the story, the relationship between them is often intense on both sides. They are—and to an extent must be—obsessed with one another, if only for the sake of survival.

It’s worth noting that the characters do not need to have the same kind of investment. Alice could love Lucy while Lucy despises Alice. Their feelings towards one another could also be rather complicated. The important thing is that both of them go out of their way to engage in their relationship.

It should also be noted that this effort should come from the characters and not the Plot Gods. That means that the characters should be shown to have agency in their own relationship. This is one of many reasons why it’s more compelling to watch two characters fight fate to be together than it is to watch two characters who are destined for each other. The more agency that the characters take in pursuing their relationships, the more invested they appear, and so the more invested that readers will be. Make your characters seek each other out and actively steer their own relationships. A romance isn’t interesting if one character passively absorbs the other one’s affections (well, it is, but in a decidedly unromantic way). Neither is a rivalry where one character mercilessly taunts another, unprovoked and without retaliation.

I’m not feeling this conflict anymore so stop pursing me–We’re so over!

You can use the idea of mutual investment to purposely disrupt chemistry because, believe it or not, there are places where you don’t want chemistry. A good way of signaling that a relationship will not work out is to demonstrate that the investment is not mutual. Pulling away, dismissive behavior, and visible apathy all put the breaks on relationship development pretty quickly and make any claims of personal attachment appear much weaker. Note that this is effective when breaking apart a romance or a friendship, but works poorly when used on nemeses. It’s one thing for Lucy to give her good friend Alice the cold shoulder. It’s another if she decides she’s had it with the villain, and emotionally checks out. The first alters a character relationship in a meaningful way and adds tension to the story, especially if Lucy isn’t ready to let go. The second suggests that Alice isn’t scared of the villain, lowers the stakes, and undercuts the perceived danger.

Check back next Monday for part two!

Have any characters with great chemistry? Tell us about them!