“Evil” came to a conclusion much like it began — with its protagonist confronting the enigma of evil in front of her.

Four seasons ago, viewers met New York-based forensic psychologist Kristen Bouchard (Katja Herbers) as she was assessing the mental capacity of a serial killer whose lawyer suggests that his client is possessed by a demon after he murdered three families but claimed to have no memory of the killings. Now, she has uprooted to Rome with her family, including her son Timothy — the purported Antichrist — whom she now has care over.

In the closing moments of the series finale, “Fear the End,” she’s startled when the baby’s eyes flicker to white and sharp fangs briefly appear along his gums, signaling that something is amiss. But the mother carries ahead with her workday, choosing to ignore the concerning development.

It’s a moment that underscores how much the character has evolved in the intervening years after becoming an assessor of potential demonic possession and other supernatural occurrences for the Catholic Church — alongside her work besties, priest David Acosta (Mike Colter) and tech whiz Ben Shakir (Aasif Mandvi). It also showed how her motherly instincts have guided her decisions all along and will continue.

This interview with Robert and Michelle King, the husband-and-wife creators of “Evil,” and Herbers has been edited for clarity and length.

Q: Finales can be tricky things to pull off, given how invested viewers are with the characters and their hopes for them, and how immediate their feedback can be. What was your vision for the ending of “Evil”?

Michelle King: We wanted to end the story in a way that was satisfying to the viewers and felt like a conclusion and, yet, still allowed for the option of telling more stories, if that were ever a possibility.

Robert King: In general, our attitude toward endings is cheerful cynicism. That it’s something that left you, hopefully, with a smile, but also is honest enough to say, in this case, evil doesn’t go away. Evil is there. But at least Kristen and David are in the same universe. Everybody that the audience cares about is still alive, and yet, that’s honest to what’s going on right now.

Q: Had you known how you wanted to end the series from the start, or was it something that revealed itself later?

RK: I think later, with the trope of the Antichrist and the idea of nurture versus nature. The question always at the end of the series was nature versus nurture, and I think it got changed — I’d loved to hear Katja’s thoughts on this because it changed on the set through Katja’s influence. In the script, she looks at the baby and isn’t sure if she saw what she saw — that there was a demented look or the eyes changed and turned red, and there were jaws. Then the light changes and it’s like, maybe it was that? Katja’s idea, which I’m thrilled by, was that she sees that it’s demonic and covers for it, which plays into the idea of mothering, which has been the very nature of the character from the very beginning.

Katja Herbers: Kristen has such a maternal instinct. Was it Season 3 where she has that nightmare, goes downstairs and finds, truly, a monster in every sense of the word, and she still wants to nurture it? She even starts breastfeeding that demon. (With that Antichrist moment,) I really wanted to tease, should somebody want to make more of the show. I liked that idea of ending it in a similar sense to the first season where (Kristen wonders), “Am I possessed or not?” And then that look (from that moment in the first season) that I remember having email conversations with Robert and Michelle about — they were looking for something that was more an amusement to the horror, which is something that Kristen’s flirted with a lot. I thought with that ending, to combine those things of “I can probably love this child enough so that it’ll turn out well, I can love the demon away” and an amusement to this idea of “What is this going to bring?”

Q: Tell me more about what your reaction was to learning Kristen’s fate, Katja. Were you surprised that, after being against it, she uprooted her family to Rome?

KH: I think if Andy weren’t out of the picture, that would not have happened. I was not surprised that she chose to do it. We’ve seen her love her job and her co-worker plenty to want to potentially make that leap. As David says, it’s only six months, and then I can decide. I love how Robert and Michelle wrote that she takes cues from her Dutch dopple(ganger). Why pass up that opportunity? She knows what life is like in Queens. That’s probably good life advice, anyway: go for it sometimes.

Q: How do you categorize what happens with the show’s most sinister character, Leland Townsend (Michael Emerson)? We don’t see him actually die.

MK: He’s always been a force to be reckoned with. By the end, they reckon with him, he is taken down. If you’re being optimistic, you will say he’s been taken down for good. They have not succumbed to murder, so they’ve triumphed ethically as well. But it’s a cabinet, and people get out of cabinets.

RK: The difficulty with doing a show that goes more than one season is, how do you keep the status quo alive but have a developing arc? And since Katja’s character had murdered in the first season and been forgiven in the second season, or ignored by the police in the second season, it was difficult to go right back to that well. Because where is the development then? So there’s an indulging into the supernatural side of the show. If there is a supernatural, this cabinet is the perfect place to hold him. And just as we saw with the second season, boxes are not always safe.

Q: We know the decision to end the show was not your own. How many more seasons would you have gone?

RK: Two more. The fifth season, which was the collapsed four episodes, would be one of those, and then one more. That always seems like a good shape for things. Also, the show very much, like all the other shows, reacts to the culture. How the world can turn 180 degrees in a heartbeat and then, and then turn again and turn again. We’re in this accelerated world that I think would become the subject of the fifth season.

Q: The dynamic between David and Kristen is something that fans really pore over — they ship them. What has interested you about the discussion within the fandom when it comes to them?

KH: I’m really in awe of people who are out there making these (video/image) edits. I just think people are so talented. I love what they choose to put in them. It’s these little gifts that you get. I like sometimes when people try to not ship me with David but are rooting for ... a genuine friendship. These people do truly care for each other and talk to each other in a very real way. We have that scene in the finale where we’re throwing our old cases in the fire and we talk about what we’re going to miss or something. David says something about talking about real things — and I think that’s a very beautiful thing to see on TV.

MK: When we did it before — the “will they, won’t they” — it was in “The Good Wife” and Alicia was just questioning whether she should stay in a tainted marriage — I don’t know how else to put it — versus go with someone she loved. Here, it feels we stacked the deck more in terms of, no, these are real obligations that they have, that the characters have. It’s not as easy as stepping away from a husband that has cheated on you very publicly. David has taken vows. Personally, I love the fact that he explodes at Ben at the end and says “I made this commitment. This commitment is hard for me, and I’m going to stick with it.” I think that’s kind of fantastic and atypical for television.