As Stranger Things fans bid farewell to the show that’s been part of their lives for nearly a decade, Jamie Campbell Bower is saying goodbye to playing not just one but three different characters.

Joining the cast in Season 4 as Vecna, Bower terrorized Hawkins as the ultimate villain, whose gruesome appearance co-creators Matt and Ross Duffer based partly on Pinhead from the Hellraiser horror films. But before he became Vecna, he was Henry Creel, the first test subject at the Hawkins Lab — whom Eleven (Millie Bobby Brown) banished to the Abyss, an alternate dimension connected to Earth via the Upside Down.

With his third iteration, Bower also portrayed Mr. Whatsit, a 1950s-styled gentleman who became an imaginary friend to Holly Wheeler (Nell Fisher) and the town’s other unsuspecting children, luring them to his house to help carry out his monstrous acts.

In the series’ explosive finale, Vecna finally meets his demise after a battle waged by our heroes, with Joyce Byers (Winona Ryder) wielding an axe and delivering the last blow that decapitates Vecna. It’s a gory end to a murderous reign, but even in that moment, with blood spurting from his mouth, Bower’s performance is so poignant that you almost feel empathy for Vecna.

“As I’m coughing up this bile, yes, I’m coughing, but the feeling that I want to convey and the words that I’m trying to get out are just, ‘Please don’t,’” Bower says. “It was one of the more human moments of playing Vecna.”

Below, Bower — who recently electrified fans when he made a surprise cameo as Henry Creel in the Broadway production of Stranger Things: The First Shadow — reflects on how Henry morphed into Vecna and his feelings on the show’s final bow.

What was it like playing three characters this season?

Jamie Campbell Bower: Variation is always interesting and being put out of your comfort zone is always interesting. The hardest challenge for me was having had a manifesto in Episode 7 in Season 4 to then going into a situation where I have to lie. What I ended up doing was looking for pockets of truth within the lie, so I didn’t feel like I was presenting the lie completely. It was mainly about justification and fear. Fear is ultimately one of the things that rules this character so much this season.

What has been the most rewarding part of playing Vecna?

Bower: Through my interactions with people outside the show, what’s wildly rewarding is knowing people can understand him, that he’s not just some anarchic, crazed lunatic. He has his truth and his story. If I meet people and they say, “Oh, I know how that feels,” I’m like, “Good, because me too.” The fact that it worked is really rewarding. The fact that people found Vecna scary is really rewarding.

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What was the most challenging scene for you this season?

Bower: There’s a three-camera locked-off shot where I’m shifting between Vecna, Henry, and Mr. Whatsit, and I’d rehearsed maybe 30 seconds of movement to match. On the day, director Frank Darabont needed more, so I just cut loose and matched that over and over again. That was tough, physically really hard. Another challenge was sometimes filming with photo doubles instead of the real kids, which makes it hard to bounce off people. Shooting out of order was tough, too. Sometimes it felt like driving in the dark without headlights, but I have no doubt something beautiful will come out of it. I love the stunt work. I love being up on the wire.

What was it like filming the mine shaft scene, and what does it mean for Henry?

Bower: I’m chasing Holly through the desert, and she runs into this mine shaft, which represents a repressed memory of a traumatic experience for Henry, the reason his whole life ended up the way it has. He finds a briefcase with a black rock that pours into his hand and changes everything. It’s the reason he lost his youth, his childhood, his love, his heart. Then Will comes into the mine and tells him he can resist, but Henry says, “No, it showed me that this world is broken, that man is broken.” It was the first moment in Season 5 I truly felt human again and understood him. I felt like I’ve been wanting to protect him all this time because I felt like all the people just hate him. And it was in that moment that I was like, “Now you see. Now you see why I am.”

What was your reaction to the Pain Tree set?

Bower: I saw a photograph of it first at a Halloween party and someone said, “Look at what we’re lighting tomorrow.” I thought, “Oh my God, that looks amazing.” I did this on Season 4 with Vecna’s Mind Lair — any set that big, you want to walk onto it and feel like you own the space. The first time I saw it, it was in isolation, which was cool. It was nice to feel like, “OK, this is my home. This is where I’m residing, and it’s magical. It’s ginormous.”

How did it feel to put down Henry/Vecna for the last time?

Bower: There’s great sadness because while I know I’ll see everyone again in some capacity, we’re not all going to be together again. We’re not going to make something all together again. That’s a sad reality of sharing your life with a group for four or five years. Shooting this season, we see each other all the time, through good and bad parts, and we become family, we become each other’s support system. It’s magical to experience that. So yeah, sad, relieved, confused, excited, terrified.

What’s your take on how the series comes to an end?

Bower: As a fan, it’s a beautiful, heartfelt, heartwarming moment. Fans will really feel like it’s come to its natural close. The way Matt and Ross write, the original kids all have such beautiful things to say to one another, and it’s really special.

What will you miss most about working on this show?

Bower: I know what I’m going to miss most: It’s the people. It’s not the magic of making film or the moments on camera, as beautiful as they are. That doesn’t happen without being with and around these people. It takes a village. So yeah, my friends.

Do you have a message for the fans?

Bower: Just thank you for letting us into your lives.

This interview has been edited for length and clarity.