Upgrade Soul has an immediately provocative conceit: elderly couple Molly and Hank Nonnar decide to undergo an experimental rejuvenation procedure and are inadvertently cloned. Molly's and Hank's clones, dubbed Manuela and Henry, are superior to Molly and Hank in every way, except, the pair thinks, in the way they look. It's here that Upgrade Soul asks its central question: what do we mean by "better"?

It soon becomes clear that only one version of each can survive, and the story's drama derives from the characters having to determine which is the truer vessel for the individual's identity. Daniels drew Manuela and Henry to look like "a combination of a 10-week-old fetus and a gummy bear," he says. "I wanted them to look appealing in a weird way but definitely ‘off.' I wanted the design to be a visual shorthand for the ambivalence everyone in the story feels for them."

That ambivalence is itself shorthand for the idea of subjectivity and is exactly why Upgrade Soul is so exceptional: the book takes a thrilling sci-fi premise and subtly asks the reader challenging questions about humanity and how we perceive and treat others, and why. "I've loved science fiction since I was a kid watching Tom Baker–era Dr. Who and Star Trek with my dad," Daniels says. "I'm interested in horror not in the form of a mindless, bloodthirsty monster but in the form that asks if that monster has ever been in love.

Or if that monster likes music, or when was the last time that monster cried? The most memorable moment in the Alien franchise isn't any of the countless times someone gets violently stabbed through the chest with a spiked tail. It's when the alien queen wordlessly negotiates with Ripley to spare the lives of her unhatched eggs. In that moment, she's no longer just a killing machine but a living being with feelings and desires. So when Ripley torches the eggs anyway, their final confrontation is so much more loaded, meaningful, and tragic."

At the core of many sci-fi stories is fear. "I think what I'm afraid of is subjectivity," Daniels says. "When subjective ideas about ‘better' or ‘worse' are imposed upon people, the results are almost always catastrophically tragic. When certain people are arbitrarily denied the opportunity to contribute to the whole, everyone is the worse for it. Upgrade Soul isn't meant to be anti-science in any way. In fact, I'd say it's the opposite: it's anti-subjectivity. It's not the experiment that has gone wrong in this story but the subjective criteria that rejects a result that's a success in every way but the superficial."

The idea for Upgrade Soul goes back to Daniels's first day at a private art school in Portland, Ore. Daniels had been a standout teenage artist in his hometown of Sioux City, Iowa, but when he got to art school, he experienced for the first time what he recalls as "the existential terror of being rendered obsolete by someone who could do everything I could do better than I could do it." Upgrade Soul took 15 years to come to fruition as a published graphic novel, and Daniels is thankful for the long gestation, saying that had it been published earlier, it would have been a lesser book. Certainly, the graphic novel is suffused with a nuance and a complexity that reflects how long Daniels crafted it.

Upgrade Soul forces readers to broadly question the idea of normalcy and the privileges it grants to some but not others. "How much are we defined by our faults and failings?" Daniels asks. "How much of our identity is formed by the ease or difficulty with which we move through the world, whether it's because of our race, age, disability, gender, or even disposition?"