He recalls: “Most secondary characters, their dialogue is kind of like, ‘Good job, Buffy. What do we do now Buffy? Everybody wait for Buffy!’ and I was absolutely the opposite. ‘Sod off Buffy, you’re stupid Buffy, we’re all gonna die, Buffy.’ I think that, because as an actor, I love acting so much, I was having so much fun playing the role.

“I think that you could have both, you could have someone that was really pushing back against the good guys, and really not going along with the programme but it doesn’t get annoying, because the actor playing him is just having a delicious time doing that and so it’s fun.”

While Marsters is quick to credit the writers’ creativity, there is one storyline he wasn’t that fond of.

“The only one that I thought I had a better idea was – in season 4, they made me a cast regular and the question really becomes at that point, ‘How do you stop Spike from trying to kill Buffy?’ Because he can’t keep trying and failing. That gets redundant and it gets cheesy really fast.

“So you have to find a way to get him to stop trying to do it. And the way that they came up with was to put a chip in my head that would just make it impossible for me to kill. But I call that the Deus Ex Chip [from Deus Ex Machina]. It comes from Greek plays where you would drop a god in on a machine at the end of the play, and the god would just be like, ‘You’re evil, you’re good. You’re gonna get punished and you’re gonna get rewarded, end of play!’ and it was just a really cheap, non-imaginative way to resolve things…

“I thought it would be more interesting if Spike fell in love with Buffy. Buffy, of course, would never fall in love with Spike. That would be ridiculous, I thought. But if he fell in love with her, he could try to win her affection and fail over and over again, and you could do that in horrifying ways, you could do that in comedic ways, there’s many different kinds of iterations that you could follow that kind of game plan on.

“In that way, it would be more active for Spike in how he’s not going to try to kill her anymore, as opposed to just being prevented by a machine. That’s the only one and I’m probably not right about that either. It probably would have meant that Spike needed more screen time and with a cast that large, there’s just not that much time, you probably needed something very quick to get it done.”

He adds: “I mean, the whole thing is, how do we get this guy on without having him ruin the theme? If it had been me producing that show, I would have killed Spike off in a heartbeat. As soon as the audience said, ‘Oh, we want him. Oh, have him with Buffy. Oh, we love that character.’ Like uh-uh. He’s ruining the whole thing. I would have killed me off after probably three episodes. I’m kind of a bastard when I’m producing! I’m heartless! So I’m very lucky that they had more imagination and courage than I would have shown, frankly.”

Speaking about the writing process on Buffy, Marsters explains: “One of the reasons the Buffy writing was so good was that, to come up with an episode, the writers were being asked to come up with their worst day, the day that they don’t talk about, the day that keeps them up at night, when they really got hurt or when they really hurt someone. And then, metaphorically speaking, slap fangs on top of their dark secret, write a story about it and let the whole world know about it.

“When you would come down to a set and you would see the writer on that episode, they would almost look ashamed. Because I think they were afraid that they would be found out, that you would guess what they were actually writing about, and they didn’t want you to know that dark secret. It was a sustained act of vulnerability and courage from a core of really talented writers.”

One large conversation surrounding the Buffy finale, and Spike and Buffy’s story in general, is that of consent. One scene often spoken about is the bathroom scene in the episode Seeing Red, in which Spike attempts to rape Buffy. In the episodes preceding it, Spike and Buffy become lovers – although it’s inferred throughout their whole relationship that she never truly loves him.

Marsters recalls a female writer penning the bathroom scene in question. He said she recalled her own experience of “throwing herself” at an ex-boyfriend years before, and she wanted to “flip the sexes” to have Spike throw himself at Buffy.

“That was the crushing experience that she wanted to write about. I think that, because Buffy is a superhero and was fully capable of throwing Spike through a wall, they could flip the sexes. The point I was trying to make when I read that script was everyone who watches Buffy is Buffy, that’s the trick of storytelling…when I watch Buffy, I’m Buffy. And the people out there watching Buffy aren’t superheroes. So I’m gonna be doing this to them. You can’t flip the sexes on these characters and not have blowback, it’s going to have unintended consequences.

“The other thing is that they were very frustrated because they couldn’t convince the audience to stop rooting for Spike, they did not want the audience to say, ‘Spike and Buffy forever,’ that’s just not what they were going for. They kept having me do worse and worse things trying to get people to realise.

“Even Spike at one point goes, ‘Hey guys, I’m evil.’ Because the audience refused to do that, they finally landed on that scene. They kept having me do worse and worse things and finally they’re like, ‘OK, we’re just gonna have him do that to Buffy, like there’s nothing else that we have that’s going to make this point.’ That was another reason for that scene.

“When you know those things, maybe it will inform how you react to that scene. I don’t know if it means it was the right thing to do. I know it doesn’t seem to age well but what I want people to know is it wasn’t a cavalier decision. It wasn’t just like, ‘Oh well, these things are OK and it might be sexy and spicy if we do this.’ That wasn’t what the writers were thinking at all.

“It was very well considered and it was coming from a good place. It was the hardest day of my professional career, it sent me into therapy. I collapsed on set, I couldn’t even speak, I was shaking. That was a horrible day…when that script came, I was contracted to do anything that they said to anybody that they said to do it. I was legally compelled to do that scene. It wasn’t fun to watch probably, but it wasn’t fun to film either.”

Spike’s story ends in the finale episode, Chosen, when he sacrifices himself in a literal blaze of glory to destroy the Hellmouth – saving the lives of Buffy and her friends, and countless others.